Objective: To assess the psychometric properties of a Likert-formatted assessment instrument after altering the responses to a dichotomous format.
Design and sample: This methodological study used a 15-item instrument to obtain data from 183 participants who responded in both Likert and dichotomous formats. Response sets from each format were compared.
Measures: Each response set underwent factor analysis, Kuder-Richardson 20, Cronbach's α coefficient, item-total correlation, and parallel form equivalence tests.
Results: Factor loads of the instrument varied between .362 and .754 when responses were Likert-formatted and between .370 and .713 when responses were dichotomous. The Cronbach's α coefficient with Likert-formatted responses was .858; the Kuder-Richardson 20 coefficient of the dichotomous responses was .827. Parallel form equivalences were significant at the level of r = .753.
Conclusions: The instrument had valid results when either Likert or dichotomous responses were obtained.
Keywords: Likert; dichotomous; instrument; psychometric evaluation; scale.
© 2014 Wiley Periodicals, Inc.