Using pooled time series with random and fixed effects regression models, we examine the effect of age, period, and family life course events on a measure of religious influence on daily life in a panel of 1,339 adults interviewed three times between 1980 and 1992. The results showv a significant, non-linear increase in religiosity with age, with the greatest increase occurring between ages 18 and 30. We also found a significant decline in religiosity between 1980 and 1988, but no evidence of a period effect between 1988 and 1992. Comparison of fixed and random effects solutions found little evidence that a cohort effect accounted for the age findings. The age effect was significantly stronger for Catholics than Protestants and the lower religiosity of males was also significantly stronger for Catholics. Adding children in the range from age two to ten significantly increased religiosity, but family life course events accounted for little if any of the age effect. Prior research demonstrates substantial ambiguity regarding the extent and degree of an age effect on religiosity, the degree to which this effect reflects aging, family life cycle, or period processes, and the extent to which research findings are affected by measurement and study design. We provide additional empirical evidence on these issues by conducting random effects and fixed effects pooled-time series analyses of multiwave panel data extending over a twelve year period. Although no single technique can resolve the ageperiod-cohort riddle, this model allows us to estimate age effects controlling for cohort effects and to estimate possible period effects between 1980 and 1992. BACKGROUND The observed cross-sectional relationships between-age and religiosity are generally explained by one of three theoretical processes. The "traditional model' (Bahr 1970) focuses on developmental processes related to age per se. Alternatively, a life course model (Chaves 1991) attributes change not to developmental processes but to correlated changes in social roles, particularly in the family. A third interpretation characterizes observed variations in religiosity by age as a statistical artifact associated either with cohort replacement or period effects. The biggest controversies in studies of contemporary religiosity have been reserved for the study of period effects, specifically secularization (e.g., Chaves 1991; Firebaugh and Harley 1991; Hout and Greeley 1990). Chaves (1989) concludes there is no age effect on church attendance in the 1972-6 period, but most scholars argue that the major processes t Amy Argue i.s a doctoral candidate in the