The study by UCL researchers published this week http://onlinelibrary.wiley.com/doi/10.1111/ecoj.12181/full was interesting in its approach… looking at a 10 year window (2001 – 2011); specifically “Over the period from 2001 to 2011, European immigrants from the EU-15 countries contributed 64% more in taxes than they received in benefits. Immigrants from the Central and East European ‘accession’ countries (the ‘A10’) contributed 12% more than they received.”
A major issue with this timeframe is that we cannot consider the conditions for the A10 countries to be approximately constant in terms of ease-of-access to the UK jobs market. The scale of the difference in the numbers of immigrants from the A10 is noteworthy: in 2001 it was 20,735, in 2005 this was 228,030 and in 2011 it was 892,984. The window really matters. Furthermore, in some of the analysis within the paper they look at the window 1995 – 2011. This inconsistency in the timeframes chosen does not lead to full confidence in the results. Just how reliant are the findings on the windows chosen? The robustness measures used within the paper do nothing to check this. The period before the A10 countries joined the EU was one in which the UK performed well economically; since then the economic crisis has hit. While the research supports the conclusions that even in the downturn the EU migrants still out-contributed others, whether that contribution was sufficient to be a net positive depends on the window used.
Many longitudinal analyses are weak in this aspect. A good robustness test will check to see how much of a difference a slight change in the time window selected would have on the overall conclusions as it prevents the criticism of cherry-picking of timeframes to suit a pre-determined outcome.
To be decided 