APA Dictionary of Psychology

a representation in which interest centers on how one or more variables specifically correlate with one or more other variables, without the inclusion of a mediator or intervening variable. For example, a researcher may hypothesize that an individual’s health background relates to their coping style, which in turn may be related to the individual’s sense of well-being. A direct model of this research would focus upon how health background relates to well-being, without considering the mediator of coping style.