host population. Negative changes in market outcomes such as increases in consumer prices or decreases in wages damage consumers and workers but benefit producers and owners of assets. The net effect on household well-being is not obvious when wages and prices change. Besides increasing the labor supply and creating a demand stimulus on consumer markets, refugees can also have an impact on productivity and structural change (Paserman 2013; Hornung 2014; Braun and Kvasnicka 2014; Savimaki 2011; Peters 2017), innovation and new patents (Moser, Voena, and Waldinger 2014), create new enterprises (Akgündüz, van den Berg, and Hassink 2018; Altindag, Bakis, and Rozo) or increase FDI (Mayda, Parsons, and Vézina 2017) and trade with their countries of origin (Parsons and Vezina 2018; Ghosha and Enamib 2015; Mayda, Parsons, and Steingress 2017). The overall impact on household well-being is evidently the product of a combination of multiple factors and labor market analyses capture only some of these factors.

In our knowledge, this is the first comprehensive review of its kind. Ruiz and Vargas-Silva (2013) carried out a literature review of the impact of forced displacement on the displaced and on host communities but the review on host communities provides a brief overview of only eight papers, as most of the available literature is more recent. Related reviews on migration or the impacts of war and violence are broader in scope and have only occasional references to papers covering the impact of forced migrants on host communities. The recent reviews by Özden and Wagner (2018) and Dustmann, Schönberg and Stuhler (2016) focus on the labor market impacts of migration and only cover some of the natural experiments included in this paper. Other reviews only cover one country or region (e.g. Ogude 2017; Verwimp and Maystadt 2015; Mabiso et al. 2014). Some of the empirical papers we review offer an overview of the literature, such as Borjas and Monras (2017) and Clemens and Hunt (2017) who revisit several cases of large and sudden inflows in high-income countries, but none of these papers covers the range or scope of this work. The literature on the impacts of forced displacement on the displaced themselves was very limited until recently (see the reviews by Kondylis and Mueller 2014 and Ruiz and Vargas-Silva 2013) but has also started to grow in the last years (e.g. Gimenez-Nadal, Jose Ignacio, José Alberto Molina, and Edgar SilvaQuintero 2018; Fransen, Vargas-Silva, and Siegel 2018). The results of this literature are linked to our review as the impacts on the financial assets, human capital and psychological well-being of forced migrants will in return influence how they impact the consumer and labor markets of the host community.

Most of the papers covered are published in peer-reviewed international journals and most of these journals are top ranked journals in their respective disciplines. This set of papers is complemented by papers published as working papers in reputable series by known authors using standard modeling techniques. The oldest paper covered is dated 1990 and the newest 2018. No papers prior to 1990 were found. The episodes of FD included in this literature span from 1922 to 2015 and cover 17 of the major FD crises of this period, those that received the most attention from scholars. These are distributed between high, medium and lowincome host countries and include episodes of FD in the US and Europe, Middle East, North-Africa, SubSaharan Africa and Latin America. Only empirical papers in economics with original results are covered by the review.

Almost all studies are described as _natural experiments_ by the authors but face major measurement and identification challenges. Availability of micro data is one of the challenges and the first explanation of why these types of studies have emerged only very recently.<sup>7</sup> All studies have been undertaken _ex-post_ , after the displacement crisis has taken place. The unexpected nature of the crisis and the randomness of the allocation of displaced persons are two elements used to defend the natural experiment assumption. However, all papers address the central question of endogeneity and unobserved heterogeneity. How random is the decision to leave, the choice of destination or the type of people who flee? What other

> 7 National household surveys do not normally cover displaced populations and humanitarian agencies in charge of displaced populations do not normally cover host populations in their surveys. These latter surveys also rarely contain socio-economic information of sufficient quality to be used in econometric studies, not least because issues such as sampling and questionnaire design are extremely difficult with mobile populations such as refugees and IDPs. Registration data do not always capture the whole displaced population, might be outdated and focus on the displaced rather than host communities. Displaced people are usually hosted in marginal areas where data are scarce or of poor quality.

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