手法を比較

	順序型クロンバックのα係数	順序項目分析
分野	心理測定学	心理測定学
系統	Latent structure	Latent structure
提唱年	2007	1950s–1980s
提唱者	Zumbo, Gadermann, and Zeisser	Classical test theory tradition (Guilford, Nunnally, and others)
種類	Internal consistency reliability coefficient	Item-level diagnostic
原典	Zumbo, B. D., Gadermann, A. M., & Zeisser, C. (2007). Ordinal versions of coefficients alpha and theta for Likert rating scales. Journal of Modern Applied Statistical Methods, 6(1), 21–29.	Nunnally, J. C. & Bernstein, I. H. (1994). Psychometric Theory (3rd ed.). McGraw-Hill. ISBN: 978-0070474659
別名	alpha for ordinal data, polychoric alpha, ordinal reliability coefficient, alpha based on polychoric correlations	item analysis for ordinal data, polytomous item analysis, Likert item analysis, OIA
関連	3	6
概要	Ordinal Cronbach's alpha is a reliability coefficient computed from polychoric or polyserial correlations rather than Pearson correlations, making it appropriate for Likert-type and other ordinal item response data. It corrects the systematic downward bias that standard Cronbach's alpha produces when items are treated as continuous but are actually ordinal.	Ordinal item analysis evaluates each individual item in a rating-scale or Likert-type instrument using descriptive and correlational statistics suited to ordered categorical response formats. It guides item selection and refinement by flagging items with problematic difficulty, poor discrimination, or low corrected item-total correlations before reliability and validity studies proceed.