[Excerpt] The State-Level Paid Family and Medical Leave simulation model we developed estimates the number of family and medical leaves taken or needed in a state as well as the current employer and employee wage costs associated with those leaves. The model has the capacity to estimate the new and redistributed wage-replacement costs of any new proposed program. The simulation model relies on information collected from a survey on leave taking behavior conducted by Abt Associates for the US Department of Labor in 2012. Using this information we are able to estimate the probability of who takes a leave, what type, for how long, and based on if they receive employer pay and their own income level the use of a paid leave program. We use these probability estimates to simulate leave taking in Massachusetts using data about individuals from the American Community Survey which allows us to also estimate a host of geographic, employer, and employee characteristics about leave takers and needers. We simulate the decision to use a program versus not to use a program based on several knowable aspects that might go into this decision. These include the generosity of the program compared to employer benefits, length of leave taken, length of leave covered by the program, eligibility requirements, job protection, and individual demographics. But there are decisions to use a program that we cannot model, because these are unknown. These include ease of use, knowledge of the program, and workplace culture in the state. These later aspects will affect the take-up of the program, but we are not sure by how much.