Configuration analysis of the influencing factors of design standardization in China’s building industrialization —— Qualitative Comparative Analysis based on (fsQCA) fuzzy set

ABSTRACT

The construction industrialization will be the main development direction of building industry in the future, how to achieve building industrialization has become the focus of attention in the industry. As the core of building industrialization, design standardization is an important method to improve the efficiency and save the construction period of prefabricated buildings. The unsound design standardization is the most prominent reason that hinders the development of the whole building industrialization. How to realize design standardization in design enterprises has not been effectively solved. Questionnaire survey was used to investigate and collect data from relevant enterprises, and fuzzy set Qualitative Comparative Analysis (fsQCA) was used to analyze the data. The causal and complex influence mechanism of the configuration effect of five factors at internal and external levels on design standardization was discussed. The results show that:government and industry regulations and professional and technical personnel are sufficient and unnecessary conditions to influence design standardization;When government and industry regulations and professional and technical personnel exist at the same time or only one of them exists, design standardization can be realized by complementing other influencing factors. The conclusion provides valuable reference for future research and application in theory and practice.

KEYWORDS:

• Industrialization of architecture
• Design standardization
• Qualitative comparative analysis
• Government and industry regulation
• Professional technical personnel

1. Introduction

China’s construction industrialization is mainly characterized by design standardization, component components, construction mechanization and management informationization to achieve sustainable development of the whole industrial chain. With the attention and promotion of construction industrialization by the country and the government, standardization, as the most front-end design of construction industrialization, is the foundation and core of construction industrialization, the premise of the smooth operation of the subsequent stages and an important feature of the development of industrialization. At present, scholars have found that there are many obstacles in the process of promoting the development of construction industrialization in China, among which the imperfect design standards are still one of the most prominent factors (Zhenliang 1978). Only by achieving design standardization, can we fully consider the standardization of the industrial building system, realize the standardization of the connection nodes between prefabricated components and complete sets of equipment, and integrate all the scattered links of the construction industry into a whole. In February 2016, the State Council issued “Several Opinions of the Central Committee of the Communist Party of China and the State Council on Further Strengthening the Management of Urban Planning and Construction”, which clearly proposed to strive to make prefab buildings account for 30% of new buildings within 10 years or so. It has promoted the development of building industrialization in the direction of assembly, and the design standardization, as the core of building industrialization, will be the primary problem to be solved in order to realize the assembly building.

Since the prefabricated building has been vigorously promoted, design standardization has been studied and valued by many scholars. As a matter of fact, as early as the middle of the 20th century, the standardization of architectural design was put forward when China’s industrial and civil buildings were constructed with large-scale industrial production mode. However, the design of prefabricated buildings still adopts the standard of traditional cast-in-place mode through case investigation at present. Design standardization still cannot be realized in practical architecture. The problem is what factors affect the implementation of design standardization and how to achieve design standardization. For this reason, the existing scholars mostly discuss the factors that influence design standardization from the theoretical research. (Jin 2014) adopted analysis method, investigation method and comparison method to analyze the influences of economic, social, political, scientific and technological factors and land resources on residential building design standardization from the macro level, and found that design standardization is the product of a series of influencing factors. Liu Junying and Xu Pengpeng et al. (Polat 2010; Jie 2014; Pengpeng et al. 2018; Junying and Xi 2011) adopted field investigation and comparative analysis methods at the micro level, based on the government, market, professional and technical personnel and some factors in the design review mechanism, this paper analyzes the problems that hinder the realization of design standardization in the external environment and the design enterprises themselves, and puts forward countermeasures according to the actual situation. Some scholars (Yunfei) found that the examination and supervision should be strengthened in the design stage through questionnaire investigation, and summarized the significance of implementing design standardization. Specifically, if the design organization actively implements design standardization, it can not only shorten the design cycle, but also improve labor productivity and reduce production costs. The above research has been recognized by most scholars, that is, from the external industry market structure of the enterprise, the government and the internal enterprise itself several aspects of the analysis of the factors affecting the design standardization. However, due to the heterogeneity of external situation and structure, enterprises have different influences on the realization of design standardization. Although the above research has found the factors affecting design standardization from various aspects, due to the limitation of current research methods, it has not explored the influence of the combination of internal and external factors on design standardization, and it is difficult to explain the difference and implementation path of design standardization among enterprises.

In view of this, the Qualitative Comparative Analysis (hereinafter referred to as QCA) method is adopted below to incorporate several factors affecting design standardization in building industrialization into the same framework Analysis from an overall perspective, and to explore the complex interaction among several factors. In order to fully understand the influence path of different factor configuration on design standardization. Because QCA can explain causal complexity without losing external generalization validity, it is different from the traditional research method that believes there is a unified symmetrical relationship between variables. This method proposes a more practical asymmetrical relationship, which makes the research results more consistent with the actual situation and more convincing (Yunzhou and Dingliang 2017). Therefore, using the above advantages of QCA, this paper integrates the five main factors at the external and internal levels of design enterprises, tries to explore the relationship between the different configurations formed by them and the realization of design standardization, and excavates different paths for enterprises to achieve design standardization. The following questions mainly try to solve: What are the paths that affect the implementation of design standardization? What are the core conditions? What factors are marginal conditions? How are these paths related?

2. Literature review and analytical framework

As for the Standardization of Architectural Design, Qu Zhenliang (Zhenliang 1978) defined it as the design of buildings with different uses in accordance with unified building modules, building standards, design codes and technical regulations, etc. Through technical and economic comparison, the main parameters, performance indexes or external dimensions of buildings and components of the same type are arranged in a certain order to form a series, which simplifies the design, production and construction technology and creates conditions for concentrated and specialized production of large quantities of goods. To make the design of buildings or components and accessories have universal interchangeability in the greatest possible scope. Qu Zhenliang’s definition of architectural design standardization has been recognized by the academia and people in the industry. To be specific, first of all, the standardization is based on modular coordination center, modular coordination mainly solve the problem of product assembly of the department of the connection, realize the product components of the department of the large-scale development and design, and its absence can make component parts of the specifications of the size are not unified requirements, development and design process of nowhere, the lack of interchangeability, adapt part and part of the lack of a fixed pattern (Yan 2011), therefore, The modular coordination of parts is chosen as the index to measure the standardization of design. Secondly, the universality of parts and components is the bridge to realize the integration and modular design of standardized parts, and the way to solve the contradiction between the standardization and diversification of industrial design of buildings. Building components through the integration of new technology under the premise of standardization to achieve systematization, and ultimately rely on the socialized mass production to achieve productization. In this case, the same or different products produced by different enterprises can be applied to each other and exchanged, so as to make the industry enter a virtuous cycle, constantly improve the technical level, and provide a technical basis for the rapid production of large quantities and personalized buildings under the condition of construction industrialization. Therefore, the universality of parts and components is also used as an indicator to measure the standardization of design.

Early scholars, based on the actual situation at that time, believed that the realization of design standardization should start from improving the understanding of enterprises, and the significance of design standardization must be widely and deeply publicized (Zhenliang 1978), and discussed from the consciousness of enterprises themselves. However, the realization of design standardization does not entirely depend on the enterprise itself. Some studies have found that it is also related to the mandatory and encouraging policies of the local government where the design enterprise is located (Junying and Xi 2011). In addition, the degree of market concentration among design firms, the allocation of technical personnel within firms and the establishment of review mechanism can all promote the achievement of design standardization (Polat 2010; Jie 2014; Pengpeng et al. 2018). Therefore, it can be seen from the existing research that the factors affecting design standardization are not the only ones. It has become an indisputable fact that many factors, such as the enterprise itself and the external conditions in which the enterprise is located, affect the realization of design standardization. Although scholars agree that a variety of factors have an impact on the implementation of design standardization, due to the limitations of current methods, most of the previous studies obtained the problems affecting the implementation of design standardization through investigation analysis and proposed corresponding countermeasures, and the influence of multiple factors on design standardization could not be explored quantitatively.

To sum up, the QCA analysis method is adopted in the following, and most scholars study from the internal and external conditions of enterprises. Considering that the development level of construction industrialization in China varies with different regions, it is necessary to analyze the factors affecting design standardization from the overall perspective based on the current environment. At the same time, in July 2020, the Ministry of Housing and Urban-Rural Development issued “the Guiding Opinions on Promoting the Collaborative Development of Intelligent Construction and Construction Industrialization”, which introduced informatization into the standard production system and emphasized the combination of informatization and design standardization in construction industrialization. The following attempt is made to discuss the complex causal mechanism affecting design standardization from the perspective of five antecedent conditions at the external and internal levels of the enterprise.

2.1. External influencing factors of the enterprise

2.1.1. Market structure

The realization of design standardization means that the design enterprises are designed according to the same norms and standards, which requires the formation of a reasonable market structure among enterprises. Market concentration is the most basic and important factor to determine the market structure. Therefore, enterprises need a highly concentrated market to realize design standardization. Xue Qiang and other scholars have paid attention to the research of prefabricated promotion in Tibet Autonomous Region, which focuses on the implementation of “point to area” and strengthening the degree of market concentration, and lets a few pioneering enterprises drive the majority of enterprises to adopt standardized design, which has a good effect and is conducive to large-scale promotion from a few (Qiang et al. 2020). However, with the continuous development of the construction industry, the number of design enterprises is also increasing. However, benchmarking enterprises that can lead the industry have not been formed, and the design enterprises are highly dispersed and run independently, which makes it difficult to achieve economies of scale. Some scholars found that due to the disunity of design specifications and standards, different design institutes would provide different solutions even for the same project, leading to the fact that parts and components of various enterprises cannot be used in common with each other and it is difficult to achieve mass customization (Bing and Hailong 2015; Pengpeng et al. 2018; Qihui et al. 2016). Therefore, the strengthening of market concentration and rational planning of market structure are beneficial to the realization of design standardization.

2.1.2. Government and industry regulations

At present, the design standards of prefabricated buildings are not perfect, and there is also a lack of production and transportation standards and performance evaluation standards specifically for prefabricated buildings. There are loopholes in the policy control of relevant government departments, incomplete industrial policies and regulations, communication difficulties with stakeholders (Lei, Zhenwei, and Hongyun 2016), due to lack of standardization in the design stage of the project, and there is no complete set of modular and modular coordination principles with wide adaptability. To some extent, the lack of such policies will make the design enterprises have no basis for reference and fail to achieve design standardization. Some scholars have found that strict laws and regulations and mandatory policies are helpful to achieve design standardization. For example, Denmark formulated modular coordination legislation in the 1960s (Jaillon and Poon), which better promoted the promotion of building industrialization and achieved standardized design. Another example is that in the green building projects of domestic real estate enterprises, it is found that the mandatory policy of the government stipulates that the design standard of new buildings must be energy saving by 50%, which results in that the implementation rate has been greatly improved in the design stage (Junying and Xi 2011). Research shows that prefabricated building incentive policies can also play a role of guidance, coordination and supervision, improve the enthusiasm of design enterprises and better achieve design standardization (Lihong et al. 2020). To sum up, in the early stage of vigorously promoting the current construction industrialization, the more sound and reasonable the laws and regulations or the relevant policies are, the better the gap between the standard system of design enterprises can be narrowed, so that the parts can achieve modular coordination and mutual universality.

2.2. Internal influencing factors

2.2.1. Professional technical personnel

As the most basic and active factor of productivity in design enterprises, personnel plays an important role in the realization of design standardization. With the promotion of construction industrialization, assembly construction is gradually promoted in enterprises, and the design link is the source of the subsequent product specifications and performance. First of all, existing designers have low design level of prefabricated buildings, lack of skill training and practical experience, which may induce poor design and cause conflicts between manufacturers and designers (Polat 2008). Secondly, the simple description of the main material table in the design document may lead to rework during construction. Without detailed description of relevant standards and key performance requirements, engineering quality cannot be guaranteed, cost is out of control, and acceptance difficulty increases (Xiaoyun 2019). Some scholars also conducted research from the perspective of professional and technical personnel and found that well-trained people are more likely to control the quality of prefabricated components in a certain climate environment (Chen, Okudan, and Riley 2009). Therefore, it is believed that strengthening the training and training of the whole process of design talents and improving the coordination and communication ability of designers can ensure the design efficiency and quality and better promote the realization of architectural design standardization.

2.2.2. Application of information technology

More and more attention has been paid to the application of information technology in the process of building industrialization. In July 2020, the ministry issued “about promoting the coordinated development of intelligent building and building industrial guidance”, put forward to develop the industrialization construction, powered by digital and intelligent upgrade, promote the establishment of a standard part on the basis of specialization, scale, production system (2017), further illustrate the important effect of information technology in the construction of industrialization. BIM building information model is a widely used information technology. Its application in the design stage is conducive to modular design, the establishment of component library, and the improvement of design efficiency and design quality (Shuqiang, Qihui, and Dongfang 2017). In practical operation, design enterprises can conduct integration and collaborative design through BIM technology, review and optimize the design results. The powerful information platform can be used to expand the information model of input components and materials, so that all design majors can work together on the same platform, reduce the conflicts involved, and provide a basis for promoting the standardization and integrated design of prefabricated buildings (Lin, Ruyuan, and Hui 2019). At the same time, the establishment of the component library based on BIM will provide resource and guarantee for standardization of design, in the design process, according to the demand of the professional use of BIM component library let designers are combined to obtain the required components quickly, save design time and avoid the waste of resources, to design the implementation of the standardization play a key role.

2.2.3. Establishment of design review mechanism

The review system is mainly used in the architectural design stage and the construction stage. In order to better implement the design standardization, the enterprise needs to establish a review mechanism to supervise the process of design in real time, reduce the mistakes in the design of construction drawings, and ensure the functionality in the use, operation and maintenance stage of the building. On the relationship between design review mechanism and the implementation of design standardization, most scholars have found that the establishment of internal review mechanism is conducive to the implementation of design standardization. Xing Xuejiao et al. (Xuejiao et al. 2019) promoted the standardization and standardization of the review mechanism by simulating the informationized automatic drawing review process combined with manual review, and found that design standardization could be achieved by avoiding design loopholes as much as possible. Through investigation and research, Liang Jie (Jie 2014) found that the review and verification in the design stage have not been standardized, and the lack of implementation efforts by designers hinders the implementation of design standardization by design enterprises. Therefore, the establishment of design review mechanism by enterprises to affect the implementation of design standardization has been a consensus in the industry, but how to affect the implementation of design standardization has not been decided.

3. Research methods

3.1. Qualitative comparative analysis

Qualitative Comparative Analysis (QCA) is a set analysis method, which conceptualizes antecedent conditions and results into sets, and reveals the complex causal relationship between them by analyzing the sufficiency or necessity of the conditions to the results. These measurement variables need to be calibrated during the analysis so that the original measurements have an explicable aggregate meaning. Different from the traditional linear regression analysis method, it no longer regards the condition as independent and has a symmetric relationship with the result. In recent years, after continuous exploration and development of QCA research methods, four specific methods have been developed, including crisp set QCA (csQCA), multi-value QCA (mvQCA), fuzzy-set QCA (fsQCA) and MSDO/MDSO (system program matching cases and conditions) (Rihoux and Ragin 2018). FsQCA can deal with the problem of degree change and partial membership, that is, the case has a membership score between 0 and 1. In this paper, the anteceents (market structure, government and industry regulations, professional and technical personnel, the application of information technology and the establishment of the review mechanism) cannot be clearly divided into two factors, so fsQCA is selected for analysis. By converting fuzzy set data into truth table, fsQCA retains the advantages of truth table analysis and processing of qualitative data, limited diversity and simplified configuration, and has the dual properties of qualitative analysis and quantitative analysis (Yunzhou and Dingliang 2017).

Zhang Chi and other scholars analyzed and summarized the relevant literatures about QCA method in the field of management at home and abroad, and found that this method could solve three kinds of problems, that is, explore multiple paths leading to the same result, deal with the complex relationship between multiple antecedents, and deepen and supplement the classification method. Several advantages are summarized, among which the most important ones are low requirement on sample size and data source, advocate causal asymmetry and no special treatment for cross-layer variables (Chi, Xiaojie, and Fengbin 2017). In this paper, the influence factors of design standardization in construction industrialization are studied from the internal and external perspectives of enterprises. The following situations are faced: First, whether the conditional factors are mutually restricted or independent cannot be known, and different variables alone or interact with each other may produce the same effect; Secondly, the conditional factors themselves are subjective and fuzzy, so some variables may need to be measured in detail. Thirdly, the sample size obtained by questionnaire survey is small, so it is not possible to analyze multi-level influencing factors across layers, nor is it easy to obtain ideal results by statistical methods. QCA is suitable for small and medium-sized samples and can explore samples across different levels. Therefore, this paper uses fsQCA method to analyze the configuration of factors affecting the realization of design standardization, which provides reference for future practical work.

3.2. Data sources

Considering that the industrialization of new construction has only begun to be paid attention to and promoted in recent years, the research on relevant aspects is not sufficient, and the technology has not been implemented in some areas, there is no practical case for reference. Below mainly adopts questionnaire, will come to the conclusion that the relevant factors affecting the design in the item of questionnaire, this questionnaire is mainly to the Beijing-Tianjin-Hebei region and fabricated earlier in the development of Liaoning province government departments and design, consulting, construction and other units more than mid-level managers and designers, through summarizing their opinions and thoughts of new building industrial design standardization, to analyze the impact of several factors on the design standardization.

The questions in the questionnaire are mainly set by referring to the mature scales in previous studies, and then modified by combining the opinions of experienced experts to form the final questionnaire. Questionnaire links were sent to interviewees through telephone interviews, email, WeChat, etc. A total of 300 questionnaires were issued and 235 questionnaires were recovered. After eliminating 39 invalid questionnaires, 196 valid questionnaires were finally obtained with a recovery rate of 65.33%. Before data analysis, sample characteristics of the questionnaire were analyzed, as shown in Table 1.

Table 1. Sample characteristics.

Working unit	Sample	The proportion (100%)	Hours engaged in assembly work	Sample	The proportion (100%)
The government department	32	16.33%	1–3 years	73	37.24
Real estate enterprise	33	16.84%	4–6 years	68	34.69
Design Consulting Unit	38	19.39%	7–9 years	35	17.86
Construction unit	40	20.41%	More than ten years	20	10.2
Supervision unit	26	13.26%
Research institutions	27	13.77%

Due to the fact that the respondents were completed independently in the filling process, which may lead to the Common Methods Variance (CMV) of the data, clear and concise items were adopted as far as possible in this study, and the respondents were asked to fill in the questionnaire anonymously. After sorting out the data, Harman single factor detection method was used to conduct unrotated principal component factor analysis on all the items, and it was concluded that the CMV of principal component was 25.55%, indicating that the principal component only explained 25.55% variation (less than 50%). Therefore, it can be concluded that there is no serious homology bias in the survey data.

3.3. Measurement and calibration of antecedent factors and interpreted results

The data of each variable was obtained mainly through Likert five-point scale (1 means “strongly disagree” and 5 means “strongly agree”). In order to ensure the reliability and validity of the scale, the variables were measured by referring to mature scales in authoritative journals at home and abroad as much as possible, and meanwhile, constant discussions were made with experts and scholars to make them more in line with the research situation of this paper. Through reliability and validity analysis, the final questionnaire was obtained.

3.3.1. Antecedent factors

For the market structure, the measurement scale of Wang Chunting (Chunting, 2015) was referred, and three questions were set by combining relevant literature and consulting results. Government and industry regulation can be divided into three dimensions: command-control regulation, economic incentive regulation, and industry laws and regulations. It mainly refers to the research scale design of scholars Khanna and Damon (Khanna and Damon) and Zhang Menghao (Menghao 2016), and combined with the consulting results, a total of 6 questions are designed. Professional and technical talents can be divided into two dimensions: the technical level of designers and talent cultivation. The six items to measure professional and technical talents are determined by referring to the measurement scale of scholars Zhang Nan (Nan 2016) and Sadafi (Sadafi, Zain, and Jamil 2012). The application of information technology mainly refers to the measurement indexes of scholars Xie Yulong (Yulong 2016) and Venkatesh&Davis (Venkatesh et al. 2003). Determine 6 items to measure the application of information technology; The design of the review mechanism mainly refers to the scales of scholars Xie Fei (Fei, Ming, and Qing 2018) and He Weiyi (Weiyi et al. 2014), as well as the opinions of experts, and sets up three questions related to the review mechanism.

3.3.2. Interpreted results

Design standardization. Throughout the history of industrialization, we find that it is impossible to achieve standardization if there is no systematic dimensional coordination. The ultimate goal of the implementation of design standardization is to standardize the quality, specification, type and scale of architectural components, and to make mass customization of architectural components, fittings and equipment with large usage, wide range, strong versatility and many commonalities (Devine-Wright 2013). Therefore, modular coordination and generalization of components are selected as measuring indexes in this paper. The measurement scheme proposed by Sang Peidong (Peidong and Jinxiao 2017) and Sadafi (Sadafi, Zain, and Jamil 2012) was mainly referred to, and 4 questions were obtained by consulting relevant professionals for appropriate modification.

3.3.3. Calibration of variables

After obtaining the data, according to the substantive theoretical knowledge, the original scale values of all causes, conditions and results are converted into fuzzy membership scores by using the calibration method. The core of this method is to define three qualitative anchor points: the threshold value of full membership, the crossing point and the threshold value of complete non-membership. After transformation, the aggregate membership is between 0 and 1. Using FSQCA3.0 software and referring to the studies of scholars such as Fiss (Fiss 2011), Kraus (Kraus, Ribeiro-Soriano, and Schüssler 2018) and Pappas & Woodside(Pappas and Woodside 2021), “4” was set as full-set membership, “3” as the intersection point, and “2” as full-set non-membership. By setting these three thresholds, run the command “compute” on the other variables to automatically perform the calibration conversion. The calibration anchor points for each variable are shown in Table 2.

Table 2. Calibration information of influencing factors of design standardization in building industrialization.

Variable		Fuzzy set calibration
		Full-set non-membership	Intersection	Full-set membership
External factors of enterprise	Market structure	2	3	4
	Government and industry regulation	2	3	4
Enterprise internal factors	Professional technical personnel	2	3	4
	The application of information technology	2	3	4
	The establishment of design review mechanism	2	3	4
Design standardization	Module coordination of component parts	2	3	4
	The parts are universal	2	3	4

3.4. Reliability and validity test

SPSS24.0 and AMOS23.0 were used to analyze the reliability and validity of the scale. The relevant data results are shown in Tables 3 and Table 4. In terms of reliability, it was found that Cronbach’s and CR values of all variables were above 0.8, indicating that the scale had good reliability. In terms of validity, it was found that the KMO value of each variable was between 0.743 and 0.909, and the Bartlett spherical test was at a significant level. The standard factor load of all items was above 0.7, indicating that the scale had good structural validity and aggregate validity.

Table 3. Reliability and validity analysis of variables.

Variable	Target item	Load factor	Cronbach’s α	CR	KMO	AVE
Market structure (M)	M1	0.845	0.874	0.882	0.743	0.714
	M2	0.820
	M3	0.869
Government and industry regulation (G)	G1	0.811	0.931	0.928	0.889	0.691
	G2	0.858
	G3	0.822
	G4	0.802
	G5	0.839
	G6	0.853
Professional technical personnel (P)	P1	0.890	0.955	0.955	0.909	0.780
	P2	0.882
	P3	0.880
	P4	0.893
	P5	0.870
	P6	0.885
Application of information technology (I)	I1	0.774	0.941	0.945	0.905	0.733
	I2	0.897
	I3	0.874
	I4	0.842
	I5	0.881
	I6	0.849
The establishment of design review mechanism (D)	D1	0.919	0.912	0.916	0.753	0.783
	D2	0.881
	D3	0.854
Design standardization (S)	S1	0.934	0.930	0.950	0.865	0.825
	S2	0.921
	S3	0.883
	S4	0.894

Table 4. Global fit coefficient table.

χ^2/df	RMSEA	CFI	IFI	TLI
2.185	0.078	0.917	0.917	0.909

4. Research results

4.1. Necessity analysis

After each variable was calibrated, fsQCA3.0 was used to conduct necessity analysis on all antecedent conditions to evaluate whether necessary conditions existed for the formation of design standardization. In fsQCA, if a condition is always present when the result occurs, it is considered a necessary condition. In general, when the consistency level is higher than 0.9, this condition can be identified as a necessary condition for the occurrence of the result (Stroe, Parida, and Wincent 2018). Table 5 is the results of analysis of necessary conditions for design standardization. It can be found that the consistency between government and industry regulations and professional and technical personnel is between 0.8 and 0.9, indicating that these two explanatory variables are sufficient and unnecessary conditions for influencing standardization in design stage (Baogui and Xin 2020). It also refers to the independent appearance of a variable in government and industry regulations and professional and technical personnel, which is likely to achieve design standardization. On the contrary, the path and way that influence the realization of design standardization are not limited to these two, there are still other paths and ways to find. The consistency rate and necessity coverage rate of all single conditions did not exceed the threshold value of 0.9 (the identification standard of necessary level). It is shown that there are no necessary conditions for the realization of standardized design among the 5 conditions: market organization, government regulation, professional technical personnel, application of information technology and design review mechanism, which need to be combined together for analysis. Therefore, it is necessary to conduct multivariate configuration analysis.

Table 5. Analysis of necessary conditions for design standardization.

Conditions	The results
	Consistency	Coverage
Market structure	0.720135	0.750387
~ Market structure	0.356668	0.623890
Government and industry regulation	0.867021	0.698936
~ Government and industry regulation	0.178295	0.612947
Professional technical personnel	0.839597	0.815326
~ Professional technical personnel	0.225565	0.449689
Application of information technology	0.592546	0.716012
~ Application of information technology	0.474724	0.674512
The establishment of design review mechanism	0.702867	0.713684
~ The establishment of design review mechanism	0.343542	0.628592

4.2. Antecedent conditional configuration

With the help of the truth table, the sufficiency analysis was carried out to define the conditional combination (configuration) sufficient for the result to occur in the causal relationship(Stroe, Parida, and Wincent 2018). In this paper, fsQCA was used to analyze the corresponding data, and the frequency threshold was set as 2, and the consistency threshold was set as 0.8 to evaluate the causal adequacy. The “Standard Analysis” program is run with design standardization as the result variable, and the corresponding complex solution, intermediate solution and simplified solution are obtained, and the implementation paths affecting design standardization are analyzed accordingly. Table 6 shows the configuration results formed by the 5 conditions. It can be seen that the consistency level of the 4 configurations presented in the table is higher than the minimum acceptable consistency level of 0.75 for both the single solution and the overall solution. The coverage of the overall solution is 0.953, showing a fairly high coverage in the sample. Moreover, this means that all 4 configurations can fully explain the existence of the results and can be regarded as a combination of sufficient conditions to help enterprises achieve design standardization.

Table 6. Logical conditional combination of factors influencing design standardization.

Condition variables	Logical conditional combination
	解1	解2	解3	解4
Market structure		⊗	●	●
Government and industry regulation	●	●	●	⊗
Professional technical personnel	●	●		●
Application of information technology	●		●	⊗
The establishment of design review mechanism		●	●	⊗
Consistency	0.925486	0.949039	0.955035	1
Raw coverage	0.438628	0.548558	0.401594	0.136495
Unique coverage	0.143215	0.262052	0.13673	0.0925856
Total consistency	0.930073
The total coverage	0.953464

Note: ●represents the configuration of the core conditions exist, ⊗represents the core conditions are absent, ●represent edge conditions exist, ⊗represents the edge conditions are absent, “blank” configuration of the condition can also can be absent.

Under the complex action of internal and external factors, there are four configurations of influencing factors of design standardization in building industrialization, namely, configurations 1, 2, 3 and 4. The consistency level of configuration 1 is 0.925, and the raw coverage is 0.439. In this configuration, the application of information technology, government and industry regulations and professional and technical personnel exist as the core conditions. It shows that design standardization can be achieved when the design enterprise is in an external environment with sound policies and regulations, and at the same time, it has professional technical personnel and advanced information technology inside the enterprise. Because the characteristics of the building is the need for all parties to cooperate, design enterprises only have a high level of design, proficient in the multi-stage professional technical personnel, coupled with the application of information technology, in order to accurately and timely identify and understand the key information; With the application of information technology, information feedback and sharing can be achieved. To implement the standardization of prefabricated buildings, relevant information of production, transportation and installation should be collected in the design stage in advance so that the design results can be implemented (Shuqiang, Qihui, and Dongfang 2017). At the same time, a project may require the joint participation of dozens of units. Only in an intelligent information platform for communication and sharing can massive information be unified and consistent (Zuyan, Jinhui, and Yuanqi 2016). In the government and related policy of positive conditions, enterprises have a high professional quality design talents, can better understand the pros and cons of the policy, through the information platform for communication and coordination to avoid design error and change, thus enterprise has the ability to have conditions to meet the design standardization, design the product to achieve modular coordination and generalization.

The consistency of configuration 2 is 0.949, and the raw coverage is 0.549, which means that the proportion of the cases covered by the given configuration is 54.9%. In this configuration, government and industry regulations, professional and technical personnel and design review mechanism are the core factors, and the market structure is absent as the marginal conditions. It shows that even without a relatively concentrated market, design firms can achieve design standardization. Specifically, it refers to the design of normative laws and regulations and industrial systems outside the enterprise, so that the enterprise can correctly fulfill the mandatory policies and make reasonable use of the encouraging policies; Internal has a professional technical personnel operation; There is a sound design review mechanism for restriction and supervision. Professional and technical personnel work under the guidance of the enterprise’s internal review specifications and corresponding standards, so that the design results are in line with the corresponding specifications, to avoid rework after review by the government review department, which can save design time and cost. And the design results can fully meet the principle of modular coordination and universality, building and parts, parts and parts form a fixed pattern.

The consistency level of configurational 3 is 0.955, and the raw coverage is 0.402. In this configurational 3, government and industry regulation, application of information technology and design review mechanism exist as core conditions, and market structure exists as auxiliary conditions. For design enterprises, design work is based on strict laws and regulations, and sound standards and norms. Reasonable application of information technology in enterprises can stimulate the inspiration of designers through the display of three-dimensional graphics and greatly improve the designers on the basis of their original business capabilities (Jiefeng and Xinghui 2014). A perfect design review mechanism has been established to ensure the professional operation of designers. At the same time, information technology can be organically combined with the design review mechanism, to achieve the operation of designers timely feedback, tracking their work results, to avoid the occurrence of violations, and constantly improve and improve the consistency of design results and standards. Improve the efficiency and accuracy of the review (Xuejiao et al. 2019). In the highly concentrated market, enterprises can share technology and resources through the information platform, improve problems in design, achieve win-win cooperation and improve the corresponding technology level and design experience (Junying and Xi 2011), and the products can also be produced in large quantities without difference.

The consistency level of configurational 4 is 1, which is the highest among all configurations, and the raw coverage is 0.136. Market structure and professional and technical personnel exist as the core conditions, while government and industry regulation, application of information technology and establishment of design review mechanism are absent as the marginal conditions. Namely, when the market structure forms a scale, the overall concentration among the design firms is high, and through mutual communication, the firms can reach a relatively uniform standard; In this case, the enterprise has professional technical personnel will be unified standards in the application of the design results, and the design chart of the standard to give a detailed description, for the design stage to provide the most favorable technical support. Even if the other conditions are good, the highly centralized market and the skilled design talents in the design enterprise can achieve the unified design mode through communication among the design enterprises, so as to realize the design standardization.

4.3. Robustness test

In order to test the robustness of analysis results, this study adjusted the variable data calibration method and changed the crossover critical value of variables between −25% and 25%(Fiss 2011). For example, the calibration standard of design standardization was adjusted to (4, 3.02, 2). The results showed that the relevant data only changed slightly and the interpretation of the results did not change substantially, as shown in Table 7. Therefore, the configurational results in this paper are robust.

Table 7. Logical condition combination of influencing factors of design standardization (Adjusting calibration standard).

Condition variables	Logical conditional combination
	解1	解2	解3	解4
Market structure		⊗	●	●
Government and industry regulation	●	●	●	⊗
Professional technical personnel	●	●		●
Application of information technology	●		●	⊗
The establishment of design review mechanism		●	●	⊗
Consistency	0.92323	0.94809	0.953567	1
Raw coverage	0.436193	0.546572	0.398981	0.137721
Unique coverage	0.144614	0.26369	0.137407	0.0939285
Total consistency	0.931297
The total coverage	0.953251

5. Conclusions and implications

5.1. Research conclusions

Through the data collection of questionnaire survey, the combined effect of five factors on the design standardization of China’s industrial construction enterprises is discussed from the internal and external aspects of the design enterprises by using the fsQCA research method which is most consistent with the architecture thinking. The main conclusions of this study are as follows: (1) Government and industry regulations and professional and technical personnel are sufficient and unnecessary conditions to affect design standardization. In other words, it is possible to realize design standardization if a variable of government and industry regulation and professional and technical personnel appears separately. On the contrary, the development path and way to realize design standardization is not limited to this, there are still other paths and ways to explore; (2) When the government and industry regulations and professional and technical personnel exist at the same time, there are two ways to affect the realization of design standardization. The first path refers to the perfection of government and industry regulations, the existence of professional and technical personnel in enterprises and the application of information technology. The second path refers to the perfection of government and industry regulations, professional and technical personnel within the enterprise and the establishment of a sound design review mechanism. (3) When government and industry regulations exist separately, there is a path to affect the realization of design standardization, which specifically refers to the highly centralized market of the enterprise, the perfection of government and industry regulations, the application of information technology in the enterprise and the establishment of a sound design review mechanism. (4) When there is a lack of government and industry regulation, there is only professional and technical personnel inside the enterprise, there is a way to affect the realization of design standardization, specifically refers to the design enterprise has well-trained technical personnel inside, there is a reasonable market structure, and the high concentration among enterprises.

5.2. Theoretical value

Five factors, including market structure, government and industry regulation, professional and technical personnel, application of information technology and establishment of design review mechanism, are included into the research framework to explore the combined effect of their influence on design standardization of industrial construction enterprises, which enriches the research method. Most of the previous studies discussed the linear relationship between some of the factors and the outcome variables, ignoring the complexity of causality. In fact, the internal and external factors of the enterprise in different dimensions will achieve the effect of “all paths lead to the same destination”. Based on this, the research strictly followed the mode of configurational thinking, introduced the fsQCA method, which combined the advantages of qualitative and quantitative research, into the analysis of influencing factors of design standardization, and used fsQCA3.0 software to calculate the results of corresponding indicators for reference of previous theoretical research. It was found that no single factor constituted a necessary condition to affect design standardization. The factors affecting the implementation of design standardization are essentially the equivalent results of multiple internal and external factors. The fsQCA method adopted in this paper is an effective supplement to the traditional regression method. The research is carried out with the way of thinking of configuration, which clarifies the influence of internal and external factors on the implementation of design standardization to a certain extent and solves the limitations of previous studies. It provides a reference for the later research on the influencing factors of design standardization.

5.3. Practical enlightenment

At present, China attaches great importance to the development of construction industrialization(2017). Whether the design standardization as the front-end will be achieved will have a significant impact on the subsequent work arrangement, time limit and even cost. Therefore, this study has certain practical reference value for Chinese enterprises implementing construction industrialization. As enterprises in all walks of life living under the environment, they are mainly faced with the influence of internal and external factors, so are construction enterprises. Under the dynamic environment, construction enterprises can build a complete design system and realize design standardization according to their own characteristics and external factors, rather than just analyzing and demonstrating the degree of influence of a certain factor on design standardization. To be specific, first of all, enterprises should always pay attention to the changes in the overall environment, comply with the requirements of The Times, abide by the relevant regulations of the government and the industry, actively respond to the government’s encouragement policies, and provide more convenience for their own work. Secondly, it is necessary to attach importance to the improvement of design standardization skills of the internal personnel of the enterprise, train and introduce high-quality talents, strengthen the professional team of the enterprise, improve the technical level, quality and professional awareness of relevant personnel, and provide technical support for the realization of design standardization. Under the current environment, construction industrialization continues to be valued and promoted, and relevant favorable policies are constantly introduced. As the front end of the design enterprises, they should evaluate the situation and seize the opportunity. The above two points have important influence on the realization of design standardization.

In addition, if not limited by capital and ability, enterprises should expand their business scope, establish contact with other enterprises through information communication and social exchange, constantly carry out internal reform and enhance competitiveness, form a strong market scale, and achieve open sharing of design standards among enterprises. A certain market size can make the enterprises in the industry gather together, which is conducive to the unification of the designed products and the reduction of the differences between products. If there are detailed policy support or sophisticated technical personnel, each enterprise can also according to their own technology reasonable division of labor, improve the design level and efficiency, for the later production, installation to provide a greater guarantee. In order to avoid the uncertainty of external factors, enterprises should pay attention to the internal perfection and improvement. First of all, enterprises standing in the new era should develop digitalization and intelligence to the maximum extent, build a powerful information platform, give full play to the fast and powerful attributes of information technology, break time and geographical limitations, and carry out information communication and sharing at any time. With the application of information technology, enterprises can timely identify the changes and updates of external policies, as well as the timely adjustment of internal organizational structure and personnel, providing sufficient conditions for the realization of design standardization; Secondly, for the enterprise, without external factors, enterprises also need to further improve the internal design review mechanism, it can be for technical personnel have the effect of constraint, avoid drawing errors and rework, inspire designers potential, actively use information technology or to learn new knowledge and skills, to achieve modular coordination design products and to achieve standardization of design. At present, enterprises should not blindly pursue the perfection of certain factors, but should correctly recognize their own advantages and disadvantages, make full use of their own advantages to integrate enterprise resources, avoid their own disadvantages to seize opportunities, make full use of internal and external resources, and realize design standardization on a certain path.

6. Limitations and prospects of the research

This research still has some deficiencies, the limitation lies in: (1) a specimen with a key fabricated Beijing-Tianjin-Hebei and promote early enterprise of Liaoning province as the main research object, the regional representative sample has certain limitations, with the deepening of the state of construction industrialization promotion, Suggestions of follow-up studies can be extended to other areas, make the research conclusion more universality; (2) As the qualitative comparative analysis method of fuzzy sets requires the number of explanatory variables, and considering the representation of variables, data availability and timeliness, the scope and depth of influencing factors that can be studied in this paper are limited, and there are still other influencing factors to be further discovered; (3) With the promotion of building industrialization, prefab building market has formed a certain scale, in practice there will be a lot of successful implementation of design standardization of prefab integrated construction enterprises, future research can consider the selection of representative cases for in-depth analysis. The influence factor analysis of design standardization from various aspects is more beneficial to prove the universality and guidance of the conclusion.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Yongli Yue

Yue Yongli (1995-), female, Tongliao, Inner Mongolia, master, mainly engaged in the research of architectural industrialization.