Models that have appeared in the student attrition literature in the past decade and behavioral models from the social sciences that may help explain the dropout process are examined, and an attempt is made to synthesize a causal model of student attrition. The models of Tinto, Spady, and Rootman in the area of student attrition, and models of student participation (Boshier), status attainment (Sewell and Hauser), turnover in work organizations (Price), suicide (Durkheim), and the relation between intentions and behavior (Fishbein and Ajzen) are addressed. Bean's industrial model of student attrition and Pascarella's model concerning student/faculty informal contacts are also included. The synthetic model identifies four classes of variables: background variables, organizational variables, environmental variables, and attitudinal and outcome variables, all of which have direct or indirect effects on intent to leave, which is the immediate precursor of dropping out. Variables can be added to or deleted from the model to match the particular needs of an institution. Twenty-three variables that may be important predictors of dropping out are identified. The relative causal importance of these variables to dropping out can be assessed using stepwise multiple regression analysis in a path analytic framework. In addition, effects coefficients can indicate the total contributions of one variable on dropping out in terms of both indirect and direct effects. Charts that depict the various models and a bibliography are included. (SW)