Marital Adjustment over the Family Life Cycle: The Issue of Curvilinearity

Marital adjustment over the family life cycle is reexamined using data from probability samples of married couples studied in coordinated research projects in three different states—Iowa, Ohio, and Georgia. The paper attempts to provide both a methodological and substantive contribution by (1) introducing techniques of curvilinear regression and correlation data analyses to address empirically the questions raised by the findings of some previous studies which imply that a curvilinear or second order polynomial function describes the relationship between marital adjustment and stage of the family life cycle, and (2) using these techniques to examine our collective data from 1584 respondents who completed the Locke-Wallace Marital Adjustment Scale and responded to questions about social background variables and stage of the family life cycle. While demonstrating that the techniques of analysis presented are appropriate and necessary to answer the research question, our substantive findings lend only limited support for the previously implied significance of curvilinearity. Misleading interpretations which follow from a cross-sectional design as opposed to a more appropriate longitudinal design are considered. It is suggested that authors of previous cross-sectional studies supplement these present findings by reanalyzing their data and that future studies employ these more appropriate methods.