Table 2.

Confirmatory factor analysis of four measurement models of PIUQ-9.

	χ2	df	p	CFI	TLI	RMSEA	RMSEA pclose	SRMR	SSABIC
ITALIAN VERSION (n = 1,346)
3-factor model	192.2	24	<0.001	0.941	0.912	0.072 [0.063–0.082]	<0.001	0.050
2-factor model	245.7	26	<0.001	0.923	0.893	0.079 [0.070–0.088]	<0.001	0.053
Bifactor model with 3 specific factorsc	116.4	19	<0.001	0.966	0.935	0.062 [0.051–0.073]	0.034	0.031	30801.9
Bifactor model with 2 specific factorsf	103.7	19	<0.001	0.970	0.944	0.058 [0.047–0.069]	0.117	0.029	30782.5
GERMAN VERSION (n = 1,190)
3-factor model	152.2	24	<0.001	0.941	0.911	0.067 [0.057–0.077]	0.003	0.050
2-factor model	225.5	26	<0.001	0.908	0.873	0.080 [0.071–0.090]	<0.001	0.058
Bifactor model with 3 specific factorsd	58.5	19	<0.001	0.982	0.966	0.042 [0.030–0.054]	0.856	0.025	24887.3
Bifactor model with 2 specific factors	49.3	18	<0.001	0.986	0.971	0.038 [0.026–0.051]	0.932	0.018	24864.7
FRENCH VERSION (n = 1,030)
3-factor model	245.4	24	<0.001	0.893	0.839	0.095 [0.084–0.106]	<0.001	0.059
2-factor model	258.9	26	<0.001	0.887	0.844	0.093 [0.083–0.104]	<0.001	0.059
Bifactor model with 3 specific factors	139.8	18	<0.001	0.941	0.882	0.081 [0.069–0.094]	<0.001	0.039	23986.1
Bifactor model with 2 specific factors	98.2	18	<0.001	0.961	0.922	0.066 [0.053–0.079]	0.019	0.031	23935.0
POLISH VERSION (n = 548)
3-factor model	149.7	24	<0.001	0.909	0.864	0.098 [0.083–0.113]	<0.001	0.058
2-factor model	154.7	26	<0.001	0.907	0.871	0.095 [0.081–0.110]	<0.001	0.058
Bifactor model with 3 specific factorsc	103.6	19	<0.001	0.939	0.884	0.090 [0.074–0.107]	<0.001	0.042	12530.5
Bifactor model with 2 specific factors	68.7	18	<0.001	0.963	0.927	0.072 [0.054–0.090]	0.022	0.030	12488.1
SPANISH VERSION (n = 473)
3-factor model*	104.1	24	<0.001	0.923	0.885	0.084 [0.068–0.101]	<0.001	0.051
2-factor model	111.7	26	<0.001	0.918	0.886	0.083 [0.068–0.100]	<0.001	0.052
Bifactor model with 3 specific factorse	65.9	19	<0.001	0.955	0.915	0.072 [0.054–0.092]	0.026	0.038	10599.9
Bifactor model with 2.specific factors	47.3	18	<0.001	0.972	0.944	0.059 [0.039–0.079]	0.221	0.030	10566.0
TURKISH VERSION (n = 432)
3-factor model	70.8	24	<0.001	0.964	0.946	0.067 [0.049–0.086]	0.056	0.037
2-factor model	73.3	26	<0.001	0.964	0.950	0.065 [0.048–0.083]	0.076	0.036
Bifactor model with 3 specific factorsc	42.7	19	0.001	0.982	0.965	0.054 [0.032–0.075]	0.359	0.027	10171.0
Bifactor model with 2 specific factorsb	25.9	19	0.133	0.995	0.990	0.029 [0.000–0.054]	0.905	0.018	10147.9
HUNGARIAN VERSION (n = 245)
3-factor model	97.4	24	<0.001	0.884	0.826	0.112 [0.089–0.135]	<0.001	0.066
2-factor model	107.1	26	<0.001	0.872	0.822	0.113 [0.091–0.135]	<0.001	0.066
Bifactor model with 3 specific factors	70.2	18	<0.001	0.917	0.835	0.109 [0.083–0.136]	<0.001	0.044	5618.7
Bifactor model with 2 specific factorsb	57.0	19	<0.001	0.940	0.886	0.090 [0.064–0.118]	0.008	0.035	5604.2
ENGLISH VERSION (n = 175)
3-factor model	51.4	24	<0.001	0.931	0.897	0.081 [0.050–0.111]	0.050	0.062
2-factor model	96.8	26	<0.001	0.822	0.753	0.125 [0.099–0.152]	<0.001	0.079
Bifactor model with 3 specific factorse	38.7	19	0.005	0.950	0.906	0.077 [0.041–0.112]	0.097	0.048	4360.4
Bifactor model with 2 specific factorsb	24.5	19	0.176	0.986	0.974	0.041 [0.000–0.082]	0.595	0.036	4346.4
GREEK VERSION (n = 154)
3-factor modela	43.5	24	0.009	0.963	0.944	0.073 [0.036–0.107]	0.134	0.042
2-factor model	45.2	26	0.011	0.964	0.950	0.069 [0.033–0.102]	0.166	0.044
Bifactor model with 3 specific factorsb,e	29.5	20	0.078	0.982	0.967	0.056 [0.000–0.096]	0.379	0.031	3636.9
Bifactor model with 2 specific factorsb	25.0	19	0.160	0.989	0.978	0.045 [0.000–0.089]	0.524	0.028	3634.4

PIUQ-9, Problematic Internet Use Questionnaire−9 items; CFI, comparative fit index; TLI, Tucker-Lewis Index; RMSEA, root-mean-square error of approximation; SRMR, standardized root mean residual; SSABIC, sample-size adjusted Bayesian Information Criteria.

^aError message (the model is instable due to a correlation larger than 1 between Control disorder and Neglect factors).

^bResidual variance of item 1 is fixed to zero.

^cResidual variance of item 4 is fixed to zero.

^dResidual variance of item 8 is fixed to zero.

^eResidual variance of item 5 is fixed to zero.

^fResidual variance of item 6 is fixed to zero.