Dataset for Rasch analyses of the brief Critical Thinking Scale (CTh) and assessment of change Data from the study reported in ” Exploring first semester changes in domain-specific critical thinking”. Data are from Danish Psychology students, and consists of three data sets containing the variables described below. Baseline data set (n = 336) Gender: 1 = female, 2 = male Agegroup (median split): 1 = 21 years and younger, 2 = 22 years and older Math (perception of own mathematical knowledge as adequate): 1 = inadequate, 2 = adequate Statfuture (expectation to need statistics in future employment): 1 = yes, 2 = maybe, 3 = no CTh1, CTh2, CTh5 are items of the CTh scale with response scale (item statements included in the article): 1 = never, 2 = rarely, 3 = sometimes, 4 = often, 5 = always RescaledWML (rescaled person parameter estimates at baseline) Matched longitunial data set dataset (n = 165) Gender, Agegroup, Math and Statfuture were collected at baseline Gender: 1 = female, 2 = male Agegroup (median split): 1 = 21 years and younger, 2 = 22 years and older Math (perception of own mathematical knowledge as adequate): 1 = inadequate, 2 = adequate Statfuture (expectation to need statistics in future employment): 1 = yes, 2 = maybe, 3 = no CTh1b, CTh2b, CTh5b are items of the CTh scale at baseline with response scale (item statements included in the article): 1 = never, 2 = rarely, 3 = sometimes, 4 = often, 5 = always CTh1f, CTh2f, CTh5f are items of the CTh scale at follow-up with response scale (item statements included in the article): 1 = never, 2 = rarely, 3 = sometimes, 4 = often, 5 = always RescaledWMLf (rescaled person parameter estimates at follow-up)