%0 Journal Article %T Assessing the Significance of Cohort and Period Effects in Hierarchical Age-Period-Cohort Models: Applications to Verbal Test Scores and Voter Turnout in U.S. Presidential Elections %A Frenk, Steven M. %A Yang, Yang Claire %A Land, Kenneth C. %D 2013 %P 221-248 %J Social Forces %V 92 %I 1 %2 ISSN: 0037-7732