Basic Scale on Insomnia complaints and Quality of Sleep (BaSIQS): Reliability, initial validity and normative scores in higher education students

Abstract

Based on successive samples totaling more than 5000 higher education students, we scrutinized the reliability, structure, initial validity and normative scores of a brief self-report seven-item scale to screen for the continuum of nighttime insomnia complaints/perceived sleep quality, used by our team for more than a decade, henceforth labeled the Basic Scale on Insomnia complaints and Quality of Sleep (BaSIQS). In study/sample 1 (n = 1654), the items were developed based on part of a larger survey on higher education sleep–wake patterns. The test–retest study was conducted in an independent small group (n = 33) with a 2–8 week gap. In study/sample 2 (n = 360), focused mainly on validity, the BaSIQS was completed together with the Pittsburgh Sleep Quality Index (PSQI). In study 3, a large recent sample of students from universities all over the country (n = 2995) answered the BaSIQS items, based on which normative scores were determined, and an additional question on perceived sleep problems in order to further analyze the scale’s validity. Regarding reliability, Cronbach alpha coefficients were systematically higher than 0.7, and the test–retest correlation coefficient was greater than 0.8. Structure analyses revealed consistently satisfactory two-factor and single-factor solutions. Concerning validity analyses, BaSIQS scores were significantly correlated with PSQI component scores and overall score (r = 0.652 corresponding to a large association); mean scores were significantly higher in those students classifying themselves as having sleep problems (p < 0.0001, d = 0.99 corresponding to a large effect size). In conclusion, the BaSIQS is very easy to administer, and appears to be a reliable and valid scale in higher education students. It might be a convenient short tool in research and applied settings to rapidly assess sleep quality or screen for insomnia complaints, and it may be easily used in other populations with minor adaptations.

• Higher education students
• psychometric analyses
• self-response questionnaire
• sleep quality

ACKNOWLEDGEMENTS

We are grateful to the colleagues and students who helped during data collection. Thanks are also due to the Department of Education of the University of Aveiro, which supported the materials for the questionnaire printing of the second sample.

DECLARATION OF INTEREST

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Successive research studies leading to this work have been supported by different entities: Department of Education, University of Aveiro; Projects LEIES (FCG-Portugal) and SPASHE (FCT-Portugal); and Research Units CCPSF and CIECC (FCT-Portugal).

Partial results from this study have been previously presented at the World Congress on Sleep Medicine in 2013 (WASM-2013) and were published as a congress abstract. The BaSIQS items have been in use by our research team for more than a decade, so Cronbach alpha values have been reported in academic dissertations (cf. references in the text). However, no previous publication has been dedicated to scrutinizing the full psychometric properties of this scale, and until now, the only single value which was previously published in a journal article was the Cronbach alpha coefficient found for the first sample. Therefore, this article is dedicated to presenting original research results derived from first-hand psychometric analysis that were not previously addressed or published in any other journal article.