The taxometrics of marriage: is marital discord categorical?

This study used taxometric methods to investigate the latent structure of the construct of marital adjustment as indexed by the Marital Adjustment Test (MAT; H. J. Locke & K. M. Wallace, 1959). That is, the authors examined whether marital adjustment is best thought of as a “dimension” of adjustment only or whether there also are categorical differences between “discordant” and “nondiscordant” couples. Analyses of data provided by 447 couples married for approximately 2 years provided converging evidence for a latent category of marital discord, suggesting that marital discord can be viewed as a qualitatively distinct state experienced by approximately 20% of the couples in the current sample. Implications for marital assessment are outlined. Marital researchers variously characterize couples as maritally “dissatisfied,” “distressed,” or “discordant,” often using these terms interchangeably. However, categorizing couples as “discordant” versus “nondiscordant” implies that a qualitative distinction can be drawn between distressed and nondistressed couples. Further, categorization itself, regardless of the label used, implies a belief that researchers are able to correctly assign couples to the appropriate category using currently available measures. In the absence of a true criterion measure, this belief may appear either tautological or perhaps merely untestable (Heyman, FeldbauKohn, Ehrensaft, Langhinrichsen-Rohling, & O’Leary, 2001). That is, even though it is conventional to designate a couple as discordant if the mean couple score is below 97 on the Dyadic Adjustment Scale (Spanier, 1976) or if the summed couple score is 200 or below on the Marital Adjustment Test (MAT; Locke & Wallace, 1959), these cutpoints cannot be shown to be better than any number of other possible alternative cutpoints in the absence of a true criterion. At the same time, one cannot determine the convergent validity of a proposed criterion measure in the absence of nonarbitrary cutpoints on commonly used marital scales. Accordingly, the marital area would seem to be in a “Catch 22” situation: We cannot easily proceed with the development of a criterion measure of marital discord without identifying nonarbitrary cutpoints for commonly used marital inventories, but we cannot readily validate particular cutpoints for these measures without a true criterion measure of marital discord. Of course, the use of any cutpoint begs the question of whether there really is a qualitatively different state of “marital discord” and, if so, whether commonly used marital adjustment scales provide useful indicators of this qualitatively different state. The answer to this question has profound implications for research and theory in the marital area. If evidence of a categorical difference between maritally discordant and nondiscordant couples is found, this would provide powerful support for the argument that it is both necessary and desirable to develop a criterion measure of marital discord (Heyman et al., 2001). At the same time, if information about the approximate frequency of marital discord could be found, this would provide guidance for efforts to develop such a criterion measure. Conversely, because dichotomizing a variable that should be treated as continuous is equivalent to discarding more than a third of one’s sample (Cohen, 1983), if marital discord has no latent categorical properties, this would suggest that one should not dichotomize couples into discordant and nondiscordant categories. This would also be an argument against the development of a categorical criterion measure of marital discord.