OLD Ethnibus 0.138, ONS 0.465; all p<0.01). (Minus signs simply reﬂect different directions of coding). Multivariable analyses Multivariable analyses were conducted with each sample in order to examine independent predictors of the OPQOL, CASP- 19 and WHOQOL-OLD. For comparability, the same indepen- dent variables were entered into each model. On the basis of the literature,7 optimum scores on each measure were hypothesised to be associated with optimum QoL: self-rated active ageing, independent self-ratings of QoL domains, social activities and help from social network members, self-rated health status and physical functioning (ADL), age, sex, marital status and housing tenure. The QoL follow-up sample also provided an opportunity to test the causal model underpinning the OPQOL. OPQOL The cross-sectional model for the QoL follow-up sample was highly signiﬁcant (see table 1). Perceptions of ageing more actively, having optimal self-ratings of health, independence, home and neighbourhood, psychological well-being and ﬁnances, more social activities and female sex signiﬁcantly, and inde- pendently, predicted optimal OPQOL scores. The amount of explained variance of OPQOL scores in the model was high at 77% (adjusted R2 0.774). The OPQOL models in the ONS and Ethnibus samples were also highly signiﬁcant. Again, optimal ratings of active ageing, most self-rated QoL domains and also self-rated health status were signiﬁcant in both samples. The model explained 65% of the variance in OPQOL scores (adjusted R2 0.653) in the ONS sample and 43% (adjusted R2 0.430) in the Ethnibus sample (table 2). The variables included in the test of the causal model under- pinning the OPQOL, in the QoL follow-up sample, were the baseline indicators that reﬂected the components chosen for the OPQOL domains (health and functional status, practical help received, social support and activities, perceived quality of neighbourhood, psychological outlook, GAP score for social comparisons and expectations and self-efﬁcacy), plus standard sociodemographic indications to control for their effects. This model explained 56% of the variance in OPQOL scores (adjusted R2: 0.563). As number of different social activities was not signiﬁcant in the model, a reduced model was conducted excluding this variable. Health status and number of diagnosed medical conditions, help and social support, perceptions of neighbourhood and feeling safe, social comparisons (comparing one’s ﬁnancial and living circumstances with others who are worse off), feelings of self-efﬁcacy and control, then explained 48% of the variance in OPQOL scores in expected directions (adjusted R2 0.481). The overall model was highly signiﬁcant in general support of the OPQOL (see table 3). CASP-19 The CASP-19 was assessed in the two ONS and Ethnibus samples. The amount of explained variance in CASP-19 scores in the ONS sample explained by the model was 57% (adjusted R2 0.568); the model was highly signiﬁcant, and in expected direc- tions. The variables that retained signiﬁcance in the model were ﬁve of the domain ratings, health and functioning. In contrast, the CASP-19 model for the Ethnibus sample was weak: the amount of explained variance in CASP-19 scores was just 14% (adjusted R2 0.141), although the model was still signiﬁcant. The variables that were signiﬁcant were self-rated active ageing, and three of the seven QoL domain self-ratings, health status, but not physical functioning (see table 4). J Epidemiol Community Health 2011;65:273e280. doi:10.1136/jech.2009.087668 Research report Table 3 Causal model underpinning OPQOL Unstandardised 95% CI (Two-tailed B t test) Independent predictor variables Standardised b p Value Final model 5 Block 1 Self-rated health compared with others of same age No. of diagnosed medical conditions Block 2 No. of ﬁve listed areas can call for help and support with Married/cohabiting versus single, widowed, divorced Block 3 Self-rating of neighbourhood score (quality, problems) Feels safe walking alone day6night score 3.850 0.099 Block 4 GAP score: social comparisons worse, same or better off than others Self-efﬁcacy score Block 5 Age Sex 4.220 0.318 1.710 0.136 6.368 0.132 2.811 0.097 3.176 0.199 7.440 0.227 2.145 0.155 0.486 0.221 3.077 0.109 5.643 to 2.798 ( 5.846) 0.0001 3.016 to 0.404 ( 2.579) 0.011 1.837 to 10.900 (2.769) 0.006 5.724 to 0.103 ( 1.901) 0.059 NS 4.665 to 1.688 ( 4.205) 0.0001 0.268 to 7.433 (2.118) 0.035 10. 504 to 4.376 ( 4.784) 0.0001 3.461 to 0.829 ( 3.211) 0.002 0.698 to 0.274 ( 4.510) 0.001 0.402 to 5.751 (2.267) 0.024 1.999 to 4.297 (0.719) 0.473 NS Housing tenure: home-owner/mortgage 1.149 versus rent/other 0.035 Constant R2 Adjusted R2 Anova F statistic; p value 175.666 0.505 0.481 21.629; 0.0001 ADL, activities of daily living; NS, not statistically signiﬁcant at least the 0.05 level; OPQOL, Older People’s Quality of Life. Multiple regression of baseline (1999/2000) predictors of OPQOL at follow-up (2007/2008): QoL follow-up sample (ﬁnal model). WHOQOL-OLD The WHOQOL-OLD was assessed in the ONS and Ethnibus samples The amount of explained variance in WHOQOL-OLD scores in the ONS Omnibus survey was 45% (adjusted R2 0.448); the model was highly signiﬁcant, again in expected directions. The signiﬁcant variables were self-rated active ageing, three of the seven QoL domain ratings and the number of social activities and helpers, health status and housing tenure. However, the WHOQOL-OLD model for the Ethnibus sample was weak, although signiﬁcant: the amount of explained vari- ance in WHOQOL-OLD scores was just 5% (adjusted R2 0.048). The signiﬁcant variables were three of the seven domain ratings, and number of social activities (see table 5). CONCLUSION This study describes the psychometric performance of a QoL questionnaire, developed from the perspectives of older people 277