Age effects and health appraisal: a meta-analysis.

OBJECTIVE: The purpose was to clarify the effects of methodological variables in the research on age differences in self-rated health and specifically the effects of: (a) the item type used to solicit the appraisal, (b) the approach to sampling, and (c) the criteria for assembling the age groups for study.
METHODS: Studies differing on these dimensions were compared using meta-analytic techniques. Seventeen usable samples were grouped according to the age comparisons--seven compared "young" and "old" samples while ten compared "young-old" and "old-old" groups.
RESULTS: The results failed to support the frequently reported health optimism of old-old samples when compared with young-old. Further, the findings suggest that the item type used in eliciting the rating of health may be instrumental in the respondent's appraisal process. For instance, use of the age-comparative item tends to favor "old" groups when compared to young, whereas the global health item has an effect in the other direction. Effect size was also related to a study's sampling procedure and to the method used in assembling groups (i.e., age ranges used to represent young and old). DISCUSSION: Practical implications and areas of needed research are discussed.