evidence that murder rates in these countries do influence the flow, there's work by economist michael clemensshowing for each additional murder there's a large increase in the number of asylum seekers from those countries coming to the united states but there's also evidence they are coming here for economic opportunity. a lot of them have family members in the u.s. who can hook them up with jobs once they get here. u.s. rates of economic growth combined with job opportunities here combined with the fact they can enter mexico much more easily lawfully in many cases now, because mexico reformed its immigration laws, as well as with the increasingly bad crime situation in central america, i think all the main factors why they're coming here. in terms of what effect they have on u.s. crime, when they get here, the evidence is pretty clear they are much less likely to be incarcerated than native-born americans in u.s. prisons and from the one state we have evidence for, they are less likely to be convicted of crimes once they come into the united states and even are less likely to be arrested for