Table 2 presents the results of baseline and fitted MIMIC models testing for birth cohort measurement invariance for current FTND models using birth <1945 as the reference. This model demonstrated poor fit (X2= 4364.34 (39), p<.001) with comparative fit index (CFI)=0.478 and root mean square error of approximation (RMSEA)=0.108 and a worsening fit with adjustment for FTND measurement non-invariance (X2=4213.75 (20), p<.001, CFI=0.495, and RMSEA=0.123) (Hu and Bentler, 1999). Results evaluating measurement invariance for current FTND using 1945–1975 as a reference group were largely similar to analyses using <1945 as the reference, including a low level of measurement non-invariance that accounted for little of the model variance and did not greatly affect the modelling results when invariance was adjusted for (Table S2)1.
