Longitudinal studies of school leavers also provide evidence for the exposure hypothesis. As mentioned earlier, school leaver studies are less likely to be confounded by anticipation effects than are studies of mature age job-losers. Nevertheless, negative psychological effects of both unemployment and unsatisfactory employment have been shown in studies by Dooley and Prause (2000), Hammarström and Janlert (1997), O’Brien and Feather (1990), Prause and Dooley (1997), and Winefield et al. (1993).