“…Models of earnings dynamics were first proposed in the literature in the late 1970s to capture life cycle dynamics (Lillard and Willis, 1978), and have since been used extensively in the exploration of earnings inequality (Guvenen, 2009;Moffitt and Gottschalk, 2002;Baker and Solon, 2003;Cappellari, 2004;Haider, 2001) and in mi-crosimulation modeling for the projection of social security and public pension schemes, long-term care, social welfare and taxation policy (O'Donoghue, 2001;Caldwell, 1996;Holmer et al, 2010;Toder et al, 2000;Harris and Sabelhaus, 2003). Indeed, the limitations of static earnings functions in the investigation of higher education policy have been recognised by some, with Migali (2012) incorporating stochastic variation in the growth rate of graduate earnings, and dynamic microsimulation of lifetime earnings having been applied to the modelling of higher education finance and ICLs specifically (e.g., Harding, 1995;Flannery and O'Donoghue, 2011). What has not been explored to date, however, is the extent to which ICL policy conclusions are sensitive to the earnings model assumptions used.…”