Developing a shortened version of the dementia knowledge assessment scale (DKAS-TC) with a sample in Taiwan: an item response theory approach

Table 1 Comparisons of unidimensional and 4-dimensional Rasch models and PCMs

Models	Deviance	Parameters	-2LL	AIC	BIC	RMSEA
Unidimensional Rasch model	11,023.44	26	− 5511.55	11,075.44	11,179.52	0.070
4-dimensional Rasch model	10,889.01	25	−5446.33	10,939.02	11,103.23	0.058
Unidimensional PCM	18,452.79	51	− 9226.40	18,554.79	18,759.62	0.071
4-dimensional PCM	18,324.44	60	− 9160.93	18,444.44	1862.84	0.072

Abbreviations: PCM partial credit model, −2LL 2 loglikelihood, AIC Akaike information criterion, BIC Bayesian information criterion, RMSEA root mean square error of approximation

ISSN: 1471-2318