Open AccessEFFECTS OF EXPOSURE ON PREVALENCE AND CUMULATIVE RELATIVE RISK: DIRECT AND INDIRECT EFFECTS IN A RECURSIVE HAZARD MODEL
Author(s) -
Wu Lawrence L.,
Martin Steven P.
Publication year - 2009
Publication title -
sociological methodology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.658
H-Index - 55
eISSN - 1467-9531
pISSN - 0081-1750
DOI - 10.1111/j.1467-9531.2009.01212.x
Subject(s) - covariate , demography , proportional hazards model , population , statistics , relative risk , event (particle physics) , mathematics , medicine , econometrics , confidence interval , physics , quantum mechanics , sociology
This paper outlines decomposition methods for assessing how exposure affects prevalence and cumulative relative risk. Let x denote a vector of exogenous covariates and suppose that a single dimension of time t governs two event processes T 1 and T 2 . If the occurrence of the event T 1 determines entry into the risk of the event T 2 , then subgroup variation in T 1 will affect the prevalence T 2 , even if subgroups in the population are otherwise identical. Although researchers often acknowledge this phenomenon, the literature has not provided procedures to assess the magnitude of an exposure effect of T 1 on the prevalence of T 2 . We derive decompositions that assess how variation in exposure generated by direct and indirect effects of the covariates x affect measures of absolute and relative prevalence of T 2 . We employ a parametric but highly flexible specification for baseline hazard for the T 1 and T 2 processes and use the resulting parametric proportional hazard model to illustrate the direct and indirect effects of family structure when T 1 is age at first sexual intercourse and T 2 is age at a premarital first birth for data on a cohort of non‐hispanic white U.S. women.