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Cronbach’s Alpha is not a Measure of Unidimensionality or Homogeneity

Year 2014, Volume: 2 Issue: 3, 19 - 27, 01.09.2014

Abstract

Reliability is a characteristic of scores, not tests or measurement instruments. One of the methods to estimate the reliability of the scores on a test or measurement instrument is Cronbach’s coefficient alpha method. In other words, Cronbach’s alpha is an estimate of the score reliability based on the internal consistency among the [item] scores. In addition to this, Cronbach’s coefficient alpha should not be interpreted as a measure of the test’s or the measurement instrument’s unidimensionality or taken as an index of the homogeneity of a measurement instrument. Briefly, Cronbach’s alpha is not a measure of unidimensionality or homogeneity.

References

  • Arnold, M. E. (1996). Influences on and limitations of classical test theory reliability estimates (ERIC Document Reproduction Service No. ED 395 950).
  • Bademci, V. (2001, November). To teach thinking and the methods-techniques used in instruction. Conference Hall of the SMMM Chamber, Bursa [Paper presented at the Conference, in Turkish].
  • Bademci, V. (2004). It is incorrect to speak of “the reliability of the test” or “the test is reliable”. The Journal of Turkish Educational Sciences, 2 (3), 367- 372 [in Turkish].
  • Bademci, V. (2005). On the errors inside of the arbiters evaluations: Fisher’s z transformation and sample size for reliability studies. The Journal of the Industrial Arts Education Faculty of Gazi University, 17, 46- 75 [in Turkish].
  • Bademci, V. (2006a). To put an end to the discussion: Cronbach's alpha coefficient can be used with dichotomously scored items [0,1]. Journal of Kâzım Karabekir Education Faculty, 13, 438- 446 [in Turkish].
  • Bademci, V. (2006b). To understand reliability properly and to overthrow some clichés: Contrary to the known facts, Cronbach’s coefficient alpha can be negative and smaller than “–1”. İnönü University Journal of the Faculty of Education, 7(12), 3- 26 [in Turkish].
  • Bademci, V. (2006c, April). Paradigm shift: Tests are not reliable. Conference Hall of the Vocational Education Faculty of Gazi University, Ankara [Paper presented at the Conference, in Turkish].
  • Bolton, J. E., & Humphreys, B. K. (2002). The Bournemouth Questionnaire: A short-form comprehensive outcome measure. II. psychometric properties in neck pain patients. Journal of Manipulative and Physiological Therapeutics, 25(3), 141- 148.
  • Caci, H., Nadalet, L., Staccini, P., Myquel, M., & Boyer, P. (1999). Psychometric properties of the French version of the Composite Scale of Morningness in adults. European Psychiatry, 14, 284- 290.
  • Capraro, M. M., Capraro, R. M., & Henson, R. K. (2001). Measurement error of scores on the mathematics anxiety rating scale across studies. Educational and Psychological Measurement, 61, 373- 386.
  • Caruso, J. C. (2000). Reliability generalization of the NEO personality scales. Educational and Psychological Measurement, 60, 236- 254.
  • Cortina, J. M. (1993). What is coefficient alpha? An examination of theory and applications. Journal of Applied Psychology, 78, 98- 104.
  • Cramer, K. M., & Barry, J. E. (1999). Psychometric properties and confirmatory factor analysis of the Self-Concealment Scale. Personality and Individual Differences, 27, 6296
  • Crocker, L., & Algina, J. (1986). Introduction to classical and modern test theory. Fort Worth: Holt, Rinehart and Winston.
  • Cronbach, L. J. (1951). Coefficient alpha and the internal structure of tests. Psychometrika, 16, 297- 334.
  • Gerbing, D. W., & Anderson, J. C. (1988). An updated paradigm for scale development incorporating unidimensionality and its assessment. Journal of Marketing Research, 25, Guthrie, A. C. (2000). A review of coefficient alpha and some basic tenets of classical measurement theory (ERIC Document Reproduction Service No. ED 438 307).
  • Hattie, J. (1985). Methodology review: Assessing unidimensionality of tests and items. Applied Psychological Measurement, 9, 139- 164.
  • Helms, L. S. (1999). Basic concepts in classical test theory: Tests aren’t reliable, the nature of alpha, and reliability generalization as meta-analytic method (ERIC Document Reproduction Service No. ED 427 083).
  • Helms, J. E. (2005). Challenging some misuses of reliability as reflected in evaluations of the White Racial Identity Attitude Scale (WRIAS). In R. T. Carter (Ed.), Handbook of racialcultural psychology and counseling: Theory and research, volume 1 (pp. 360- 390). Hoboken, New Jersey: John Wiley & Sons.
  • Henson, R. K. (2000). A primer on coefficient alpha (ERIC Document Reproduction Service No. ED 447 210).
  • Knapp, T. R. (1991). Coefficient alpha: Conceptualizations and anomalies. Research in Nursing and Health, 14, 457- 460.
  • Küçükdeveci, A. A., Sahin, H., Ataman, S., Griffiths, B., & Tennant, A. (2004). Issues in crosscultural validity: Example from the adaptation, reliability, and validity testing of a Turkish version of the Stanford Health Assessment Questionnaire. Arthritis & Rheumatism (Arthritis Care & Research), 51(1), 14- 19.
  • Linn, R. L., & Miller, M. D. (2005). Measurement and assessment in teaching (9th ed.). Upper Saddle River, New Jersey: Pearson.
  • Marx, R. G., Bombardier, C., Hogg-Johnson, S., & Wright, J. G. (1999). Clinimetric and psychometric strategies for development of a health measurement scale. Journal of Clinical Epidemiology, 52(2), 105- 111.
  • Mehrens, W. A., & Lehmann, I. J. (1991). Measurement and evaluation in education and psychology (4th ed.). Fort Worth : Harcourt Brace.
  • Mellenbergh, G. J. (1996). Measurement precision in test score and item response models. Psychological Methods, 1(3), 293- 299.
  • Miller, M. B. (1995). Coefficient alpha: A basic introduction from the perspectives of classical test theory and structural equation modeling. Structural Equation Modeling, 2(3), 2552
  • Mittag, K. C. & Thompson B. (2000). A national survey of AERA members’ perceptions of statistical significance tests and other statistical issues. Educational Researcher, 29(4), 14
  • Netemeyer, R. (2001). [in] Measurement. Journal of Consumer Psychology, 10(1&2), 55- 69.
  • Netemeyer, R. G., Bearden, W. O., & Sharma S. (2003). Scaling procedures: Issues and applications. Thousand Oaks, California: Sage.
  • Nunnally, J. C., & Bernstein, I. H. (1994). Psychometric theory (3rd ed.). New York: McGrawHill.
  • Pedhazur, E. J., & Schmelkin, L. P. (1991). Measurement, design, and analysis: An integrated approach. Hillsdale, New Jersey: Lawrence Erlbaum Associates.
  • Pike, C. K., & Hudson, W. W. (1998). Reliability and measurement error in the presence of homogeneity. Journal of Social Service Research, 24(1-2), 149- 163.
  • Radovanovic, C. A. T., & Alexandre, N. M. C. (2004). Validation of an instrument for patient handling assessment. Applied Ergonomics, 35, 321- 328.
  • Reinhardt, B. (1996). Factors affecting coefficient alpha: A mini Monte Carlo study. In B. Thompson (Ed.), Advances in social science methodology, volume 4 (pp. 3- 20). Greenwich, Connecticut: JAI.
  • Rogers, W. M., Schmitt, N., & Mullins, M. E. (2002). Correction for unreliability of multifactor measures: Comparison of alpha and parallel forms approaches. Organizational Research Methods, 5(2), 184- 199.
  • Schmitt, N. (1996). Uses and abuses of coefficient alpha. Psychological Assessment, 8, 350- 353.
  • Stevens, J. P. (2002). Applied multivariate statistics for the social sciences (4th ed.). Mahwah, New Jersey: Lawrence Erlbaum Associates.
  • Streiner, D. L. (2003). Starting at the beginning: An introduction to coefficient alpha and internal consistency. Journal of Personality Assessment, 80(1), 99- 103.
  • Tiesinga, L. J., Dassen, T. W. N., & Halfens, R. J. G. (1998). DUFS and DEFS: Development, reliability and validity of the Dutch Fatigue Scale and the Dutch Exertion Fatigue Scale. International Journal of Nursing Studies, 35, 115- 123.
  • Thompson, B. (1994). Guidelines for authors. Educational and Psychological Measurement, 54, Thompson, B. (1999). Five methodology errors in educational research: A pantheon of statistical significance and other faux pas. In B. Thompson (Ed.), Advances in social science methodology, volume 5 (pp. 23- 86). Stamford, Connecticut: JAI.
  • Thompson, B. (2003). Understanding reliability and coefficient alpha, really. In B. Thompson (Ed.), Score reliability (pp. 3- 30). Thousand Oaks, California: Sage.
  • Thompson, B. (2004). Exploratory and confirmatory factor analysis. Washington, DC: American Psychological Association.
  • Thompson, B., & Vacha-Haase, T. (2000). Psychometrics is datametrics: The test is not reliable. Educational and Psychological Measurement, 60, 174- 195.
  • Vacha-Haase, T., Kogan L. R., & Thompson, B. (2000). Sample compositions and variabilities in published studies versus those in test manuals: Validity of score reliability inductions. Educational and Psychological Measurement, 60, 509- 522.
  • Vacha-Haase, T., Ness, C., Nilsson, J., & Reetz, D. (1999). Practices regarding reporting of reliability coefficients: A review of three journals. The Journal of Experimental Education, 67(4), 335- 341.
  • Wilkinson, L., & APA Task Force on Statistical Inference. (1999). Statistical methods in psychology journals: Guidelines and explanations. American Psychologist, 54, 594- 604.
  • Worthen, B. R., White, K. R., Fan, X., & Sudweeks, R. R. (1999). Measurement and assessment in schools (2nd ed.). New York: Addison Wesley Longman.
  • Yin, P., & Fan, X. (2000). Assessing the reliability of Beck Depression Inventory Scores: Reliability generalization across studies. Educational and Psychological Measurement, 60, 201- 223.

Cronbach’ın Alfası, Tek Boyutluluğun veya Benzeşikliğin (Homojenliğin) Bir Ölçüsü Değildir

Year 2014, Volume: 2 Issue: 3, 19 - 27, 01.09.2014

Abstract

Güvenirlik, testler veya ölçme araçlarının değil, ölçümlerin bir özelliğidir. Cronbach’ın alfası katsayısı yöntemi, bir test ya da ölçme aracından elde edilen ölçümlerin güvenirliğini kestirme yöntemlerinden biridir. Başka bir ifadeyle, Cronbach’ın alfası, [madde] ölçümler[i] arasındaki iç tutarlılık üzerine temellenmiş bir ölçüm güvenirliğinin kestirilmesidir. Bunun yanı sıra, Cronbach’ın alfası katsayısı, ölçme aracının benzeşikliğinin (homojenliğinin) bir göstergesi olarak alınmamalı veya testin ya da ölçme aracının tek boyutluluğunun (bir boyutluluğunun) bir ölçüsü olarak yorumlanmamalıdır. Kısaca, Cronbach’ın alfası, benzeşikliğin veya tek boyutluluğun bir ölçüsü değildir.

References

  • Arnold, M. E. (1996). Influences on and limitations of classical test theory reliability estimates (ERIC Document Reproduction Service No. ED 395 950).
  • Bademci, V. (2001, November). To teach thinking and the methods-techniques used in instruction. Conference Hall of the SMMM Chamber, Bursa [Paper presented at the Conference, in Turkish].
  • Bademci, V. (2004). It is incorrect to speak of “the reliability of the test” or “the test is reliable”. The Journal of Turkish Educational Sciences, 2 (3), 367- 372 [in Turkish].
  • Bademci, V. (2005). On the errors inside of the arbiters evaluations: Fisher’s z transformation and sample size for reliability studies. The Journal of the Industrial Arts Education Faculty of Gazi University, 17, 46- 75 [in Turkish].
  • Bademci, V. (2006a). To put an end to the discussion: Cronbach's alpha coefficient can be used with dichotomously scored items [0,1]. Journal of Kâzım Karabekir Education Faculty, 13, 438- 446 [in Turkish].
  • Bademci, V. (2006b). To understand reliability properly and to overthrow some clichés: Contrary to the known facts, Cronbach’s coefficient alpha can be negative and smaller than “–1”. İnönü University Journal of the Faculty of Education, 7(12), 3- 26 [in Turkish].
  • Bademci, V. (2006c, April). Paradigm shift: Tests are not reliable. Conference Hall of the Vocational Education Faculty of Gazi University, Ankara [Paper presented at the Conference, in Turkish].
  • Bolton, J. E., & Humphreys, B. K. (2002). The Bournemouth Questionnaire: A short-form comprehensive outcome measure. II. psychometric properties in neck pain patients. Journal of Manipulative and Physiological Therapeutics, 25(3), 141- 148.
  • Caci, H., Nadalet, L., Staccini, P., Myquel, M., & Boyer, P. (1999). Psychometric properties of the French version of the Composite Scale of Morningness in adults. European Psychiatry, 14, 284- 290.
  • Capraro, M. M., Capraro, R. M., & Henson, R. K. (2001). Measurement error of scores on the mathematics anxiety rating scale across studies. Educational and Psychological Measurement, 61, 373- 386.
  • Caruso, J. C. (2000). Reliability generalization of the NEO personality scales. Educational and Psychological Measurement, 60, 236- 254.
  • Cortina, J. M. (1993). What is coefficient alpha? An examination of theory and applications. Journal of Applied Psychology, 78, 98- 104.
  • Cramer, K. M., & Barry, J. E. (1999). Psychometric properties and confirmatory factor analysis of the Self-Concealment Scale. Personality and Individual Differences, 27, 6296
  • Crocker, L., & Algina, J. (1986). Introduction to classical and modern test theory. Fort Worth: Holt, Rinehart and Winston.
  • Cronbach, L. J. (1951). Coefficient alpha and the internal structure of tests. Psychometrika, 16, 297- 334.
  • Gerbing, D. W., & Anderson, J. C. (1988). An updated paradigm for scale development incorporating unidimensionality and its assessment. Journal of Marketing Research, 25, Guthrie, A. C. (2000). A review of coefficient alpha and some basic tenets of classical measurement theory (ERIC Document Reproduction Service No. ED 438 307).
  • Hattie, J. (1985). Methodology review: Assessing unidimensionality of tests and items. Applied Psychological Measurement, 9, 139- 164.
  • Helms, L. S. (1999). Basic concepts in classical test theory: Tests aren’t reliable, the nature of alpha, and reliability generalization as meta-analytic method (ERIC Document Reproduction Service No. ED 427 083).
  • Helms, J. E. (2005). Challenging some misuses of reliability as reflected in evaluations of the White Racial Identity Attitude Scale (WRIAS). In R. T. Carter (Ed.), Handbook of racialcultural psychology and counseling: Theory and research, volume 1 (pp. 360- 390). Hoboken, New Jersey: John Wiley & Sons.
  • Henson, R. K. (2000). A primer on coefficient alpha (ERIC Document Reproduction Service No. ED 447 210).
  • Knapp, T. R. (1991). Coefficient alpha: Conceptualizations and anomalies. Research in Nursing and Health, 14, 457- 460.
  • Küçükdeveci, A. A., Sahin, H., Ataman, S., Griffiths, B., & Tennant, A. (2004). Issues in crosscultural validity: Example from the adaptation, reliability, and validity testing of a Turkish version of the Stanford Health Assessment Questionnaire. Arthritis & Rheumatism (Arthritis Care & Research), 51(1), 14- 19.
  • Linn, R. L., & Miller, M. D. (2005). Measurement and assessment in teaching (9th ed.). Upper Saddle River, New Jersey: Pearson.
  • Marx, R. G., Bombardier, C., Hogg-Johnson, S., & Wright, J. G. (1999). Clinimetric and psychometric strategies for development of a health measurement scale. Journal of Clinical Epidemiology, 52(2), 105- 111.
  • Mehrens, W. A., & Lehmann, I. J. (1991). Measurement and evaluation in education and psychology (4th ed.). Fort Worth : Harcourt Brace.
  • Mellenbergh, G. J. (1996). Measurement precision in test score and item response models. Psychological Methods, 1(3), 293- 299.
  • Miller, M. B. (1995). Coefficient alpha: A basic introduction from the perspectives of classical test theory and structural equation modeling. Structural Equation Modeling, 2(3), 2552
  • Mittag, K. C. & Thompson B. (2000). A national survey of AERA members’ perceptions of statistical significance tests and other statistical issues. Educational Researcher, 29(4), 14
  • Netemeyer, R. (2001). [in] Measurement. Journal of Consumer Psychology, 10(1&2), 55- 69.
  • Netemeyer, R. G., Bearden, W. O., & Sharma S. (2003). Scaling procedures: Issues and applications. Thousand Oaks, California: Sage.
  • Nunnally, J. C., & Bernstein, I. H. (1994). Psychometric theory (3rd ed.). New York: McGrawHill.
  • Pedhazur, E. J., & Schmelkin, L. P. (1991). Measurement, design, and analysis: An integrated approach. Hillsdale, New Jersey: Lawrence Erlbaum Associates.
  • Pike, C. K., & Hudson, W. W. (1998). Reliability and measurement error in the presence of homogeneity. Journal of Social Service Research, 24(1-2), 149- 163.
  • Radovanovic, C. A. T., & Alexandre, N. M. C. (2004). Validation of an instrument for patient handling assessment. Applied Ergonomics, 35, 321- 328.
  • Reinhardt, B. (1996). Factors affecting coefficient alpha: A mini Monte Carlo study. In B. Thompson (Ed.), Advances in social science methodology, volume 4 (pp. 3- 20). Greenwich, Connecticut: JAI.
  • Rogers, W. M., Schmitt, N., & Mullins, M. E. (2002). Correction for unreliability of multifactor measures: Comparison of alpha and parallel forms approaches. Organizational Research Methods, 5(2), 184- 199.
  • Schmitt, N. (1996). Uses and abuses of coefficient alpha. Psychological Assessment, 8, 350- 353.
  • Stevens, J. P. (2002). Applied multivariate statistics for the social sciences (4th ed.). Mahwah, New Jersey: Lawrence Erlbaum Associates.
  • Streiner, D. L. (2003). Starting at the beginning: An introduction to coefficient alpha and internal consistency. Journal of Personality Assessment, 80(1), 99- 103.
  • Tiesinga, L. J., Dassen, T. W. N., & Halfens, R. J. G. (1998). DUFS and DEFS: Development, reliability and validity of the Dutch Fatigue Scale and the Dutch Exertion Fatigue Scale. International Journal of Nursing Studies, 35, 115- 123.
  • Thompson, B. (1994). Guidelines for authors. Educational and Psychological Measurement, 54, Thompson, B. (1999). Five methodology errors in educational research: A pantheon of statistical significance and other faux pas. In B. Thompson (Ed.), Advances in social science methodology, volume 5 (pp. 23- 86). Stamford, Connecticut: JAI.
  • Thompson, B. (2003). Understanding reliability and coefficient alpha, really. In B. Thompson (Ed.), Score reliability (pp. 3- 30). Thousand Oaks, California: Sage.
  • Thompson, B. (2004). Exploratory and confirmatory factor analysis. Washington, DC: American Psychological Association.
  • Thompson, B., & Vacha-Haase, T. (2000). Psychometrics is datametrics: The test is not reliable. Educational and Psychological Measurement, 60, 174- 195.
  • Vacha-Haase, T., Kogan L. R., & Thompson, B. (2000). Sample compositions and variabilities in published studies versus those in test manuals: Validity of score reliability inductions. Educational and Psychological Measurement, 60, 509- 522.
  • Vacha-Haase, T., Ness, C., Nilsson, J., & Reetz, D. (1999). Practices regarding reporting of reliability coefficients: A review of three journals. The Journal of Experimental Education, 67(4), 335- 341.
  • Wilkinson, L., & APA Task Force on Statistical Inference. (1999). Statistical methods in psychology journals: Guidelines and explanations. American Psychologist, 54, 594- 604.
  • Worthen, B. R., White, K. R., Fan, X., & Sudweeks, R. R. (1999). Measurement and assessment in schools (2nd ed.). New York: Addison Wesley Longman.
  • Yin, P., & Fan, X. (2000). Assessing the reliability of Beck Depression Inventory Scores: Reliability generalization across studies. Educational and Psychological Measurement, 60, 201- 223.
There are 49 citations in total.

Details

Primary Language English
Journal Section Research Article
Authors

Vahit Bademci

Publication Date September 1, 2014
Submission Date June 28, 2014
Published in Issue Year 2014 Volume: 2 Issue: 3

Cite

APA Bademci, V. (2014). Cronbach’s Alpha is not a Measure of Unidimensionality or Homogeneity. Journal of Computer and Education Research, 2(3), 19-27.

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