In this study, a high proportion of 'unclear' results were observed in several items of risk of bias (Figure 2), which proved difficult for reviewers to evaluate the actual quality of the studies.
Recall bias in terms of multiple items of risk exposure was minimal.
The highest ORs for a single fall, recurrent falls, and fall-related fractures were recognized for the SRRST items of risk of falls during walking, stair ascending/descending, and wandering, respectively (Table 1).
Compared to single item measures of risk perception, the PRHS is more robust by examining multiple dimensions of perceived risk.
However, as key items for risk of bias assessment were rated unclear because of lacking information regarding representativeness and response rate, the reported results had to be considered with caution.
The evaluated items for risk of bias were as follows.
The questionnaire included 24 items regarding knowledge of preventive measures (15 items), concept of (opinion regarding) institutional measures (4 items), and perception of risk (5 items) (Appendix).
The most popular term to describe the issues relevant to this item is "quality," but for the reasons that are elaborated in box 4 we prefer to name this item as "assessment of risk of bias".
With respect to age groups, the only item at risk of DIF was 25 ('Pride in your achievements'), which was 1.05 logits more difficult for older people (t 390) = -5.00; p <0.001; M-H χ = 25.97; p <0.001).
Data on core items of selected risk factors were collected through face-to-face interview during household visits by trained interviewers using a pre-tested local version of the WHO STEPS questionnaire.
Items measuring perception of risk and seriousness were assessed on a five point Likert-type scale.
