A Meta-analysis of Empirical Evidence on the Labour Market Impact of Immigration

The number of people who are living outside their country of birth has been increasing rapidly in recent decades to some 200 million globally. The arrival of a growing number of legal and illegal migrants has raised concerns in host countries about the 'absorption capacity' of the labour market. This has fuelled extensive empirical research, not only in traditional migrant-receiving countries, but also in other high and middle income countries that attract migrants. Studies have been undertaken previously to synthesize the conclusions of this empirical research by means of formal meta-analyses of the impact of immigration on the wages of native workers and on the level of employment (Longhi et al., 2005, 2007). While these studies 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 has been severely limited by heterogeneity in study approaches, ranging from the econometric analysis of cross-regional differences to general equilibrium models and time-series approaches. In this paper we take a more qualitative approach that considers a broad range of impacts, consisting of effects on wages, employment, unemployment and labour force participation. By trichotomizing outcomes simply as a positive, negative or indiscernible impact, a relatively large database can be constructed for meta-analysis. Techniques such as ordered probit regression modelling allow an assessment of the relationship between study conclusions and key study characteristics such as type of country, methodology, period of investigation and migrant group.