Factorial validity and comparability of the six translations of the Rivermead Post-Concussion Symptoms Questionnaire translations: results from the CENTER-TBI study

Journal of Patient-Reported Outcomes

Table 5 Results of MI analyses between language samples and TBI severity groups and model comparison for the three-factor model comprising somatic, emotional, and cognitive factors using raw data [21]

Groups	Constrains	Model fit						Model comparison
Groups	Constrains	χ²	df	p	CFI	TLI	RMSEA	CI_90%	Δ χ²	Δdf	ΔCFI	ΔRMSEA	p
Language samples^a	Baseline	1633.08	606	< 0.001	0.976	0.971	0.075	[0.071, 0.080]	–	–	–	–	–
	Thresholds	1873.67	746	< 0.001	0.973	0.974	0.071	[0.067, 0.075]	164.50	140	0.003	0.004	0.077
	Thresholds and loadings	1914.19	811	< 0.001	0.974	0.977	0.068	[0.064, 0.071]	71.504	65	− 0.001	0.003	0.271
TBI severity groups (mild/moderate vs. severe)	Baseline	1028.87	202	< 0.001	0.98	0.977	0.068	[0.064, 0.072]	–	–	–	–	–
	Thresholds	1092.79	230	< 0.001	0.979	0.979	0.065	[0.061, 0.069]	40.216	28	0.001	0.003	0.063
	Thresholds and loadings	1052.98	243	< 0.001	0.981	0.981	0.061	[0.058, 0.065]	10.587	13	− 0.002	0.004	0.645

Values in bold indicate good model fit according to the respective cut-offs
^aDutch, English, Finnish, Italian, Norwegian, Spanish
χ², chi square; df, degree of freedom; χ²/df, ratio (cut-off: ≤ 2); p, p-value; CFI, Comparative Fit Index (cut-off: > 0.95); TLI, Tucker-Lewis Index (cut-off: > 0.95); RMSEA, root mean square error of approximation (cut-off: < 0.08) with 90% confidence interval (CI); Δ χ², change in chi square values between compared models; Δdf, change in degrees of freedom between compared models; ΔCFI, change in CFI between compared models (cut-off: < 0.01); ΔRMSEA, change in RMSEA between compared models (cut-off: ≤ 0.01)