,"is the change in the model's dependent variable for recipient i from 1990 to the specified current year (1991 or 1996). For the Social Security employment and SSI participation variables, the change is specified as 1 for exit and 0 for continuation;"
,"is the intercept for control group cases in the state in which recipient i resides, s (fixed state effects);"
,"is the change in the threshold for the recipient's state from 1990 to the current year, expressed as a deviation from the mean change for those in the recipient's study group;"
,"is the estimate of the effect of a change in the threshold for the control group cases;"
,"is the change in the explanatory variable Zj for recipient i from 1990 to the current year;"
,"is the estimate of the effect of a change in explanatory variable Zj for the control group cases;"
,"is a characteristic of recipient i measured in 1990;"
,"is the coefficient of Xik;"
,"is the intercept shift for the individual's study group g (g = 1, Y ,4);"
,"is the change in the threshold for the recipient's state from 1990 to the current year, expressed as a deviation from the mean change for those in the recipient's study group;"
,"is estimated effect of a threshold change on the dependent variable for those in study group g, net of the effect on the control group (g = 1, Y ,4);"
,"is the change in explanatory variable Zj for recipient i from 1990 to the current year, expressed as a deviation from the mean change for those in the recipient's study group;"
,"is the estimated effect of a change in explanatory variable Zj on the dependent variable for those in study group g, net of the effect on the control group (g = 1, Y ,4); and"
,"is the random disturbance for recipient i."