The increasing proportion of immigrants in the population of many countries has raised concerns about the ‘absorption capacity’ of the labour market, and fuelled extensive empirical research in countries that attract migrants. In previous papers we synthesized the conclusions of this empirical literature by means of meta-analyses of the impact of immigration on wages and employment of native-born workers. While we have shown that the labour market impacts in terms of wages and employment are rather small, the sample of studies available to generate comparable effect sizes was severely limited by the heterogeneity in study approaches. In the present paper, we take an encompassing approach and consider a broad range of labour market outcomes: wages, employment, unemployment and labour force participation. We compare 45 primary studies published between 1982 and 2007 for a total of 1,572 effect sizes. We trichotomise the various labour market outcomes as benefiting, harming or not affecting the native born, and use an ordered probit model to assess the relationship between this observed impact and key study characteristics such as type of country, methodology, period of investigation and type of migrant.

Longhi S., Nijkamp P., Poot J. (2008) Meta-analysis of Empirical Evidence on the Labour Market Impact of Immigration, Région et Développement, 27 (1) 161-191.
IZA Discussion Paper 3418

Immigration is a phenomenon of growing significance in many countries. Increasing social tensions are leading to political pressure to limit a further influx of foreign-born persons on the grounds that the absorption capacity of host countries has been exceeded and social cohesion threatened. There is also in public discourse a common perception of immigration resulting in economic costs, particularly with respect to wages and employment opportunities of the native born. This warrants a scientific assessment, using comparative applied research, of the empirical validity of the perception of a negative impact of immigration on labour market outcomes. We apply meta-analytic techniques to 165 estimates from 9 recent studies for various OECD countries and assess whether immigration leads to job displacement among native workers. The ‘consensus estimate’ of the decline in native-born employment following a 1 percent increase in the number of immigrants is a mere 0.024 percent. However, the impact is somewhat larger on female than on male employment. The negative employment effect is also greater in Europe than in the United States. Furthermore, the results are sensitive to the choice of the study design. For example, failure to control for endogeneity of immigration itself leads to an underestimate of its employment impact.

Longhi S., Nijkamp P., Poot J. (2008) The Impact of Immigration on the Employment of Natives in Regional Labour Markets: A Meta-Analysis, in Migration and Human Capital, ed. by J. Poot, B. Waldorf, and L. van Wissen, Edward Elgar: 173-193.
Also published as: The Fallacy of “Job Robbing”: A Meta-Analysis of Estimates of the Effect of Immigration on Employment, Journal of Migration and Refugee Issues, 1(4) 131-152 (2005).
IZA Discussion Paper 2044

In our increasingly interconnected and open world, international migration is becoming an important socioeconomic phenomenon for many countries. Since the early 1980s, many studies about the impact of immigration on host labour markets have been undertaken. Borjas (2003) noted that the estimated effect of immigration on the wage of native workers varies widely from study to study and sometimes even within the same study. In addition, these effects cluster around zero. Such a small effect is a rather surprising outcome, given that in a closed competitive labour market an increase in labour supply may be expected to exert a downward pressure on wages. We revisit this issue by applying meta‐analytic techniques to a set of 18 papers, which altogether generated 348 estimates of the percentage change in the wage of a native worker with respect to a 1 percentage point increase in the ratio of immigrants over native workers. While many studies in our database employ US data, estimates are also obtained from Germany, The Netherlands, France, Norway, Austria, Israel and Australia. Our analysis shows that results vary across countries and are inter alia related to the type of modelling approach. Technical issues such as publication bias and quality of the estimates are addressed as well.

Longhi S., Nijkamp P., Poot J. (2005) A Meta-Analytic Assessment of the Effect of Immigration on Wages, Journal of Economic Surveys, 19 (3) 451-477.