The development and psychometric evaluation of an interprofessional identity measure: Extended Professional Identity Scale (EPIS)

Figures & data

Figure 1. Study design describing five developmental stages of the Extended Professional Identity Scale (EPIS) based on scale development research (Worthington & Whittaker, 2006).

Figure 2. Flowchart of item selection and scale analysis with a predetermined number of 12 items for the final version of the Extended Professional Identity Scale (EPIS).

Figure 3. Interprofessional identity as a superordinate social identity of professional identity with three interrelated characteristics.

Table 1. Preselection based on consensus between two independent assessors (an IPE-lecturer and organizational psychologist and a dental student with IPE experience) of 35 items attributed to belonging, commitment and beliefs; sometimes adapted to the interprofessional context.

Measurement instrument	Source	Subscales	Number of items	Preselected items based on EPIT construct **
Dual Identity Scale (DIS)	Khalili, 2013	Interprofessional belonging (IPB)*	8	Belonging: 8
		Professional Belonging (PB)	10	N/A
		Dual Identity Achievement (DIA)	8	Commitment: 3
		Cross Disciplinary Attitudes (CDA)	4	N/A
University of the West of England (UWE) Interprofessional Questionnaire	Pollard, Miers, & Gilchrist, 2005	Communication an Teamwork Scale	9	N/A
		Interprofessional Learning Scale	9	N/A
		Interprofessional Interaction Scale	9	Beliefs: 2 items
		Interprofessional Relationships Scale	8	Belonging:1 item Beliefs: 1 item
Three-component Organizational Commitment Scale (OCS)	Allen & Meyer, 1990	Affective commitment	8	Commitment: 5 items
		Continuance commitment	8	N/A
		Normative commitment	8	N/A
Interprofessional Socialization and Valuing Scale (ISVS)	King et al., 2016	Comfort in working with others	9	N/A
		Ability to work with others	11	Beliefs: 2
		Value in working with others	14	Beliefs: 1
Readiness for interprofessional learning scale (RIPLS)	Parsell & Bligh, 1999	Team-work and collaboration	9	Beliefs: 3 items
		Professional identity	7	N/A
		Roles and responsibilities	3	N/A
Assessment of Interprofessional Team Collaboration Scale (AITCS)	Orchard et al., 2012	Cooperation	11	N/A
		Partnership	19	Belief: 5 items
		Coordination	7	N/A
Organizational Commitment Questionnaire (OCQ)	Mowday et al., 1979		15	Commitment: 1 item
Organizational commitment	Blau, 1985		9	Commitment: 1 item
Newly constructed items based on EPIT**	Reinders et al., 2018a		2	Belonging: 1 item Beliefs: 1 item
			205	35

*Validation items; **Extended Professional Identity Theory (Reinders, 2018; Reinders et al., 2018a); N/A = not applicable

Table 2. Shortening scale length by using EFA on 24 items (n = 97) as selected beforehand by five professionals (physician, nurse, dietitian, dental hygienist, and social worker) based on relevance (face validity) to three subscales.

Sub-scale	Item	Existing, adopted or new item	Source	Factor loadings	Top 4
Interprofessional belonging	1. I like meeting and getting to know people from other health professions.	Existing	Dual Identity Scale (Khalili, 2013)	.862	2
	2. I feel a strong attachment toward interprofessional teams comprising cross-disciplinary health professionals.	Existing		.814	3
	3. I enjoy learning and collaborating with people from other health professions.	Existing		.891	1
	4. I often feel it would be better if different health professionals work together as a team.	Existing		.666
	5. I like learning about other health professions.	Adapted		.760	4
	6. I am a health care professional who collaborates with other disciplines.	New	Constructed by the authors	.755
	7. I feel that I am respected by people from other health and social care disciplines.	Existing	UWE Interprofessional Questionnaire (Pollard et al., 2005)	.360
	8. I have a strong sense of belonging toward interprofessional teams comprising cross-disciplinary health professionals.	Existing	Dual Identity Scale (Khalili, 2013)	.724
Interprofessional commitment	1. I would be very happy to spend the rest of my career with an interprofessional team.	Adapted	Organizational Commitment Scale (OCS; Allen & Meyer, 1990)	.956	1
	2. I identify myself with other members of an interprofessional team.	Adapted	Organizational Commitment Scale (OCQ; Mowday et al., 1979)	.785	3
	3. I am proud to be a part of an interprofessional team.	Adapted	Organizational commitment (OC; Blau, 1985)	.779	4
	4. I prefer working with others in an interprofessional team.	Adapted	ISVS (King et al., 2016)	.920	2
	5. I feel able to act as a fully collaborative member of an interprofessional team.	Adapted		.625
	6. I often think about how my life will be affected by my interprofessional team membership.	Adapted	Dual Identity Scale (Khalili, 2013)	.652
	7. I have a clear sense of interprofessional collaboration and what it means for me.	Existing		.412
	8. I consider problems of an interprofessional team as my own problems.	Adapted	Organizational Commitment Scale (OCQ; Allen & Meyer, 1990)	.729
Interprofessional beliefs	1. All members of an interprofessional team should be involved in goal setting for each patient.	Adapted	AITCS (Orchard et al., 2012)	.882	2
	2. When care decisions are made, the interprofessional team members should strive for consensus on planned processes	Adapted		.715	4
	3. Interprofessional team members should jointly agree to communicate plans for patient care.	Adapted		.921	1
	4. Joint clinical decision-making should be an important part of interprofessional collaboration.	Adapted	ISVS (King et al., 2016)	.815	3
	5. My profession should be a part of an interprofessional team.	New	Constructed by the authors	.645
	6. Team-working skills are essential for all health care professionals to learn.	Adapted	RIPLS (Parsell & Bligh, 1999)	.535
	7. Patients would ultimately benefit if health care professionals work together	Adapted		.620
	8. All members of health and social care professions have equal respect for each discipline.	Existing	UWE Interprofessional Questionnaire (Pollard et al., 2005)	.440

Table 3. Polychoric and polyserial inter item correlations for each of the three subscales of the 12-item Extended Professional Identity Scale (EPIS; n = 200).

	Polychoric correlations				Polyserial
Item	1.	2.	3.	4.	correlations
1. Belonging (meeting people)	-				0.74
2. Belonging (strong attachment)	0.37	-			0.66
3. Belonging (enjoy collaborating)	0.44	0.38	-		0.81
4. Belonging (learning about)	0.59	0.40	0.44	-	0.70
1. Commitment (spend rest of career)	-				0.82
2. Commitment (identify with team)	0.49	-			0.77
3. Commitment (proud to be part)	0.67	0.51	-		0.76
4. Commitment (prefer working with)	0.49	0.50	0.48	-	0.82
1. Beliefs (involved in goal setting)	-				0.79
2. Beliefs (consensus planned processes)	0.49	-			0.76
3. Beliefs (communicate plans)	0.65	0.42	-		0.78
4. Beliefs (joint decision-making)	0.50	0.46	0.61	-	0.71

Figure 4. IRT plots of expected item scores related to expected scores of interprofessional belonging items (n = 200).

Figure 5. IRT plots of expected item scores related to expected scores of interprofessional commitment items (n = 200).

Figure 6. IRT plots of expected item scores related to expected scores of interprofessional beliefs items (n = 200).

Figure 7. Three-factor model of the Extended Professional Identity Scale (EPIS) with standardized path coefficients.

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