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Paper

Age-Period-Cohort Analysis with Noisy, Lumpy Data Brady, Henry E. Elms, Laurel Uploaded 07-14-1999 Keywords cohort analysis smoothing political participation Abstract We have developed several relatively simple methods for doing age-period-cohort analysis with noisy, lumpy data. The first method, using additional information from the Census, does not work well with our data constraints because the age composition of the population does not vary enough over relatively short periods of time. The second method, approximating APC surfaces with polynomial functions, smooths the data too much. This approach is very much a brute force curve-fitting exercise that makes a very general assumption about the functional form of the APC surface and then fits it to the data. However, a third technique we evaluate starts with a theoretically informed model of how APC effects operate for a given dependent variable. This method allows for hypothesis testing and a reasonable amount of smoothing, but probably does not smooth period effects enough. It also yields interesting results about age, period, and cohort effects. The last method we discuss briefly, combining the third technique with additional smoothing, needs more development but may improve our estimates.