The union-nonunion model of Lee (1978) investigates the joint determination of the extent of unionism and the effects of unions on wage rates. The propensity to join a union depends on the net wage gains that might result from trade union membership. The paper explicitly models the interdependence between the wage gain equation and the union membership equation.

• Adamchik and Bedi (2000) use data from Poland to examine whether there are any wage differentials of workers in the public and private sectors. The paper interprets sectoral wage differentials in terms of expected benefits and the desirability of working in a particular sector.

• Thorst (1977) models the housing-demand problem by examining the expenditures on housing services in owner-occupied and rental housing. The study models the individual decision to own or rent a house and the amount spent on housing services

似乎沒看過直接可使用之模型，有人會建議先去除組類平均 (within transformation)，然後再用一般之模型與指令。