Comparison of unweighted and item response theory-based weighted sum scoring for the Nine-Questions Depression-Rating Scale in the Northern Thai Dialect

Table 2 Item Response Theory model selection for the included participants aged ≥ 19 years (N = 1,355)

9Q Item Scoring	Group		GRM		NRM
9Q Item Scoring	Group		AIC	BIC	AIC	BIC
9Q frequency sum score	Participants		10710.43	10898.05	10730.00	11011.43
	Gender	Male	3299.51	3442.14	3315.27	3523.17
	Gender	Female	7428.65	7602.32	7442.44	7702.95
9Q unweighted sum score	Participants		13162.36	13490.68	13213.99	13776.84
	Gender	Male	4012.09	4256.61	4031.50	4439.04
		Female	9163.92	9467.86	9211.65	9732.68
9QSF combination	Participants		13688.86	14147.48	13741.36	14559.58
9QSF combination	Gender	Male	4167.76	4473.41	4200.43	4734.30
		Female	9535.17	9950.06	9578.23	10311.54

GRM graded-response model, NRM Nominal-response model, AIC Akaike information criterion, BIC Bayesian information criterion, NA Not applicable

ISSN: 1471-2288