Wide variations in employment status, wages and benefits claims are apparent between different migrant groups, research claims.
An analysis of labour market statistics found stronger "economic characteristics" among those from certain regions compared to others, according to Migration Watch UK.
The report from the think tank, which campaigns for tighter immigration restrictions, said groups with "weaker" features outnumber the others by two to one.
It said:
:: Migrants from Western Europe, India, South Africa and the 'Anglosphere' countries - the US, Australia, New Zealand - have high rates of employment at good wages and low rates of benefit claim.
:: Migrants from Africa, apart from South Africa, have overall employment rates and wages on a par with those born in the UK, but much higher rates of benefit claim.
:: Migrants from Pakistan and Bangladesh have lower rates of employment combined with lower wages and higher rates of benefit claim.
:: Migrants from Eastern Europe have high rates of employment but lower wages and higher rates of benefit claim than those born in the UK.
Migration Watch said the study raises questions about assessments of the current and future impact of immigration which assume there is no difference in the economic characteristics of migrants,
Its chairman Lord Green of Deddington said: "This analysis clearly demonstrates that sweeping claims implying that all immigration to the UK is beneficial cannot possibly be right.
"Any sensible policy should take account of the real differences in economic characteristics between migrants from different parts of the world.
"If immigration policy has been intended to attract only "the brightest and the best", it has clearly failed, with a very large number of migrants earning less or claiming more than the British born.
"The clear message of this research is that immigration can be reduced substantially while permitting entry to those migrants that our economy really needs."