cocron: A Web Interface and R Package for the Statistical Comparison of Cronbach’s Alpha Coefficients

To compare two or more measures with regard to their internal consistency reliability, Cronbach’s alpha coefficients are usually computed for each measure. For a valid comparison between Cronbach’s alpha coefficients, substantive differences need to be distinguished from circumstantial differences that occur due to chance. Unfortunately, however, popular statistics packages lack the ability to test for statistically significant differences between alpha coefficients. To remedy this problem, we present cocron, a platform-independent R package that provides functions to conduct significance tests for the comparison of two or more Cronbach’s alpha coefficients for both dependent and independent groups of participants. The cocron package is part of the R statistical computing environment and is thus available for scripting. In addition, two graphical user interfaces – a web interface and a plugin for RKWard – are offered to provide comfortable access to the functionality of cocron.

[1]  Claire Hewson,et al.  Measuring health beliefs on the Internet: A comparison of paper and Internet administrations of the Multidimensional Health Locus of Control Scale , 2005, Behavior research methods.

[2]  L. Cronbach.  Coefficient alpha and the internal structure of tests , 1951 .

[3]  F. Lord.  Sampling Error due to Choice of Split in Split-Half Reliability Coefficients , 1956 .

[4]  W. Revelle.  psych: Procedures for Personality and Psychological Research , 2017 .

[5]  J. M. Cortina,et al.  What Is Coefficient Alpha? An Examination of Theory and Applications , 1993 .

[6]  Roger Tourangeau,et al.  Should I Stay or Should I go: The Effects of Progress Feedback, Promised Task Duration, and Length of Questionnaire on Completing Web Surveys , 2011 .

[7]  A. Meade,et al.  AlphaTest: A Windows Program for Tests of Hypotheses About Coefficient Alpha , 2008 .

[8]  M. Galesic.  Dropouts on the web: Effects of interest and burden experienced during an online survey , 2007 .

[9]  C. Katona,et al.  Screening, detection and management of depression in elderly primary care attenders. I: The acceptability and performance of the 15 item Geriatric Depression Scale (GDS15) and the development of short versions. , 1994, Family practice.

[10]  Giuseppe Riva,et al.  The Use of the Internet in Psychological Research: Comparison of Online and Offline Questionnaires , 2003, Cyberpsychology Behav. Soc. Netw..

[11]  Klaus J. Templer,et al.  Internet testing: Equivalence between proctored lab and unproctored field conditions , 2008, Comput. Hum. Behav..

[12]  David J. Woodruff,et al.  Statistical Inference for Coefficient Alpha , 1987 .

[13]  Franziska Lemke,et al.  Comparison of ability tests administered online and in the laboratory , 2009, Behavior research methods.

[14]  Antonia Barke,et al.  The German Version of the Internet Addiction Test: A Validation Study , 2012, Cyberpsychology Behav. Soc. Netw..

[15]  D. McCarthy,et al.  On the sins of short-form development. , 2000, Psychological assessment.

[16]  J. Nunnally.  Psychometric Theory (2nd ed), New York: McGraw-Hill. , 1978 .

[17]  N. Schmitt.  Uses and abuses of coefficient alpha. , 1996 .

[18]  Leif D. Nelson,et al.  False-Positive Psychology , 2011, Psychological science.

[19]  Marsha L. Richins.  The Material Values Scale: Measurement Properties and Development of a Short Form , 2004 .

[20]  L. Weng,et al.  An effect size index for comparing two independent alpha coefficients. , 2005, The British journal of mathematical and statistical psychology.

[21]  M. Back,et al.  NET Will They Stay or Will They Go ? Personality Predictors of Dropout in an Online Study , 2016 .

[22]  Deen Freelon,et al.  ReCal OIR : Ordinal , Interval , and Ratio Intercoder Reliability as a Web Service , 2013 .

[23]  Stefan Rödiger,et al.  RKWard: A Comprehensive Graphical User Interface and Integrated Development Environment for Statistical Analysis with R , 2012 .

[24]  Birk Diedenhofen,et al.  cocor: A Comprehensive Solution for the Statistical Comparison of Correlations , 2015, PloS one.

[25]  G. Lautenschlager.  ALPHATST: Testing for Differences in Values of Coefficient Alpha , 1989 .

[26]  Deen Freelon.  ReCal: Intercoder Reliability Calculation as a Web Service , 2010 .

[27]  D. Streiner.  Starting at the Beginning: An Introduction to Coefficient Alpha and Internal Consistency , 2003, Journal of personality assessment.

[28]  M. Rothbart,et al.  Development and Assessment of Short and Very Short Forms of the Infant Behavior Questionnaire–Revised , 2014, Journal of personality assessment.