What does a wave of immigrants do to an economy? It was fine for Florida in 1980

There is little to no hard data showing that immigrants hurt a local economy, but there are some cases where their benefits (or lack of harm) were clearly documented: http://www.npr.org/2015/10/01/444912593/when-cuban-migrants-flooded-miami-what-did-it-do-to-the-local-economy

In the case of the "Scarface" sudden influx of 125K Cubans to South FL in 1980 (incl. 25K former criminals according to the film), there was no economic evidence of negative impact. Many were processed and enrolled in jobs/school quickly, so their need for gov't services was minor. Also they served to "grow the pie" by creating more economic demand (125K refugees = 125K consumers), which resulted in more jobs and sales for Americans. Local wages did not fall. And eventually many of them got education and contributed intellectual capital to the US. Europe, with an aging population and plummeting birth rate, actually NEEDS a lot more productive young people who are willing to work manual/unskilled jobs.

I know 1980 was a different time, and many Cubans benefited from previously-migrated relatives and a familiar culture in FL. But clearly the US will not take in 100K people from the Mideast, and they won't be concentrated in one state. As we discussed before, many Syrian refugees are educated and may also speak English, so it's not like the typical Latin American migrant profile. Detractors will come up with all sorts of excuses to oppose refugee resettlement (cost, security, culture clash), but the bottom line is they have no evidence to back up those suspicions, and as a UN member we have an obligation to act. There will always been some criminals and deadbeats among any group of people, but refugees are no worse than a random sampling of Americans (in fact they're likely better).