Using confirmatory factor analysis to manage discriminant validity issues in social pharmacy research
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Background Confirmatory factory analysis (CFA) and structural equation modelling (SEM) are increasingly used in social pharmacy research. One of the key benefits of CFA is that it allows researchers to provide evidence for the validity of internal factor structure of measurement scales. In particular, CFA can be used to provide evidence for the validity of the assertion that a hypothesized multi-dimensional scale discriminates between sub-scales. Aim This manuscript aims to provide guidance for researchers who wish to use CFA to provide evidence for the internal factor structure of measurement scales. Methods The manuscript places discriminant validity in the context of providing overall validity evidence for measurement scales. Four examples from the recent social pharmacy literature are used to critically examine the various methods which are used to establish discriminant validity. Using a hypothetical scenario, the manuscript demonstrates how commonly used output from CFA computer programs can be used to provide evidence for separateness of sub-scales within a multi-dimensional scale. Conclusion The manuscript concludes with recommendations for the conduct and reporting of studies which use CFA to provide evidence of internal factor structure of measurement scales.
KeywordsAverage variance extracted Discriminant validity Structural equation modelling
Conflicts of interest
There are no conflicts of interest in authorship of this article.
- 1.Nelson EC, Eftimovska E, Lind C, Hager A, Wasson JH, Lindblad S. Patient reported outcome measures in practice. BMJ. 2015;350. doi: 10.1136/bmj.g7818.
- 4.American Educational Research Association APA. National Council on Measurement in Education Standards for educational and psychological testing. Washington: American Psychological Association; 2014.Google Scholar
- 6.Gjalt-Jorn Y. Peters. The alpha and the omega of scale reliability and validity: why and how to abandon Cronbach’s alpha and the route towards more comprehensive assessment of scale quality. Eur Health Psychol. 2015;16(2). http://www.ehps.net/ehp/index.php/contents/article/view/ehp.v16.i2.p56. Accessed 8 Apr 2016.
- 7.Crutzen R, Peters G-JY. Scale quality: alpha is an inadequate estimate and factor-analytic evidence is needed first of all. Health Psychol Rev. 2015;1–6. doi: 10.1080/17437199.2015.1124240.
- 10.The Canadian Council for Accreditation of Pharmacy Programs. Standards for the first professional degrees in pharmacy programs. 2013. http://www.ccapp-accredit.ca/site/pdfs/university/CCAPP_accred_standards_degree_2014.pdf. Accessed 23 Apr 2015.
- 15.Lee C, Segal R, Kimberlin C, Smith WT, Weiler RM. Reliability and validity for the measurement of moral disengagement in pharmacists. Res Soc Adm Pharm. 2013;10(2):297–312.Google Scholar
- 21.Hair J, Black W, Babin B, Anderson R, Tatham R. Multivariate data analysis. Upper Saddle River: Wiley; 2006. ISBN:0130329290.Google Scholar
- 22.Raykov T. Scale reliability evaluation with LISREL 8.50. 2003. www.ssicentral.com/lisrel/techdocs/reliabil.pdf. Accessed 16 Oct 2015.
- 25.Burnham KP, Anderson DR. Model selection and multimodel inference: a practical information-theoretic approach. New York: Springer; 2002.Google Scholar