Cronbach's alpha reliability: Interval estimation, hypothesis testing, and sample size planning
Abstract
Summary Cronbach's alpha is one of the most widely used measures of reliability in the social and organizational sciences. Current practice is to report the sample value of Cronbach's alpha reliability, but a confidence interval for the population reliability value also should be reported. The traditional confidence interval for the population value of Cronbach's alpha makes an unnecessarily restrictive assumption that the multiple measurements have equal variances and equal covariances. We propose a confidence interval that does not require equal variances or equal covariances. The results of a simulation study demonstrated that the proposed method performed better than alternative methods. We also present some sample size formulas that approximate the sample size requirements for desired power or desired confidence interval precision. R functions are provided that can be used to implement the proposed confidence interval and sample size methods. Copyright © 2014 John Wiley & Sons, Ltd.
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The sample size needed for the current study was approximately 102 patients.
“the sample size needed for the current study was approximately 102 patients”
From The Psychological Flexibility in Epilepsy Questionnaire (PFEQ): Psychometric properties of the Persian version (2022) · cites this paper as [20]
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- Authors
- Bonett, D. G., & Wright, T. A.
- Affiliations
- University of California, Santa Cruz (US)
- Fordham University (US)
- Corresponding author
- Bonett, Douglas G.
- Venue
- Journal of Organizational Behavior
- Publisher
- Wiley
- Published
- 2014-10-13
- Volume
- 36
- Issue
- 1
- Pages
- 3-15
- ISSN
- 0894-3796 (ISSN-L)
- 1099-1379
- OpenAlex
- W2114299207
- Cited by
- 1,237
- References
- 23
- Citations by year
- 2026: 111 · 2025: 176 · 2024: 190 · 2023: 206 · 2022: 168 · 2021: 122 · 2020: 109 · 2019: 60 · 2018: 49 · 2017: 22 · 2016: 18 · 2015: 5 · 2014: 1
- FWCI
- 19.31
- Type
- journal article
- Language
- en
- Open access
- closed
- Licence
- Locations
- Journal of Organizational Behavior (publishedVersion)
- Topics
- Social Sciences › Decision Sciences › Management Science and Operations Research › Psychometric Methodologies and Testing
- Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Reliability and Agreement in Measurement
- Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods and Bayesian Inference
- Keywords
- Cronbach's alpha, reliability statistics, confidence intervals, interval estimation, hypothesis testing, sample size determination, heteroscedasticity, measurement reliability, statistical power
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