metadata: authors: 0: author: Rodriguez Castelan,Carlos
1: author: Vazquez,Emmanuel Jose
2: author: Winkler-Seales,Hernan Jorge
count: Mexico
docna: 0: docna: Tracing the Local Impacts of Exports on
            Poverty and Inequality in Mexico
docty: Policy Research Working Paper
abstracts: cdata!: Evidence on the effect of exports on
            welfare at the local level is scarce. Using a unique data
            set of international trade and poverty maps for almost 2,000
            Mexican municipalities between 2004 and 2014, the study
            presented in this paper provides new evidence on the impact
            of a significant rise in exports on poverty and inequality
            at the local level. The analysis implements an instrumental
            variable approach that combines the initial structure of
            exports across municipalities with global trends in exports
            from developing to developed countries by sector. The
            results show that a 10 percent increase in the ratio of
            exports to workers reduces income inequality measured by the
            Gini coefficient by 0.17 point (using a 0 to 100 scale), but
            no significant effects on poverty reduction or average
            household incomes are identified. The lack of impacts on
            average incomes is driven by a rise in the supply of labor
            at the local level because municipalities with higher export
            growth experienced an increase in labor force participation
            and attracted more net migration, particularly of unskilled
            workers. Therefore, while total labor incomes grew in
            response to an increase in exports, average labor income per
            worker did not change. Declining remittances also blunted
            the effect of growing exports on household incomes.
geo_reg_key: 119228,517191
repnme: repnme: Tracing the Local Impacts of Exports on
            Poverty and Inequality in Mexico
display_title: Tracing the Local Impacts of Exports
            on Poverty and Inequality in Mexico
listing_relative_url: /research/2020/10/32519411/tracing-local-impacts-exports-poverty-inequality-mexico
publishtoextweb_dt: 2020-10-27T00:00:00Z
origu: EFI-LCR-POV-Poverty and Equity (ELCPV)
no_of_pages: 29
author_keys: 0: author_key: 1180219
1: author_key: 1381681
2: author_key: 776733
model_extractions: Policy Research Working Paper 9459 Tracing the Local Impacts of Exports on Poverty and Inequality in Mexico _Carlos Rodríguez-Castelán Emmanuel Vazquez Hernan Winkler_ Poverty and Equity Global Practice October 2020
Policy Research Working Paper 9459

# **Abstract**

Evidence on the effect of exports on welfare at the local level is scarce. Using a unique data set of international trade and poverty maps for almost 2,000 Mexican municipalities between 2004 and 2014, the study presented in this paper provides new evidence on the impact of a significant rise in exports on poverty and inequality at the local level. The analysis implements an instrumental variable approach that combines the initial structure of exports across municipalities with global trends in exports from developing to developed countries by sector. The results show that a 10 percent increase in the ratio of exports to workers reduces income inequality measured by the Gini coefficient by 0.17 point (using a 0 to 100 scale), but no significant effects on poverty reduction or average household incomes are identified. The lack of impacts on average incomes is driven by a rise in the supply of labor at the local level because municipalities with higher export growth experienced an increase in labor force participation and attracted more net migration, particularly of unskilled workers. Therefore, while total labor incomes grew in response to an increase in exports, average labor income per worker did not change. Declining remittances also blunted the effect of growing exports on household incomes.

This paper is a product of the Poverty and Equity Global Practice. It is part of a larger effort by the World Bank to provide open access to its research and make a contribution to development policy discussions around the world. Policy Research Working Papers are also posted on the Web at http://www.worldbank.org/prwp. The authors may be contacted at crodriguezc@worldbank.org.

_The Policy Research Working Paper Series disseminates the findings of work in progress to encourage the exchange of ideas about development issues. An objective of the series is to get the findings out quickly, even if the presentations are less than fully polished. The papers carry the names of the authors and should be cited accordingly. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent._ Produced by the Research Support Team
# Tracing the Local Impacts of Exports on Poverty and Inequality in Mexico

Carlos Rodríguez-Castelán<sup>a</sup> Emmanuel Vazquez<sup>b</sup> Hernan Winkler<sup>c</sup>

**Keywords:** International trade, exports, poverty, labor markets, migration **JEL Codes:** F14, F16, I3, D3, J61

_____________________________ The authors wish to thank Raymundo M. Campos-Vasquez, Christoph Lakner, Gladys C. Lopez-Acevedo, and Ambar Narayan for their comments and suggestions. They are also grateful to participants at the World Bank authors workshop on the distributional effects of trade, the World Bank workshop on poverty and trade, and the 5th Congress Sobre Mexico organized by the Universidad Iberoamericana. The authors are indebted to Natalia Volkow and Liliana Martinez of the Microdata Center of the National Institute of Statistics and Geography, Mexico, for their support for data use in compliance with the confidentiality requirements set by Mexican law. This study received funding from the World Bank Multi-donor Umbrella Facility for Trade (UF) Trust Fund TF0A9162. The findings, interpretations, and conclusions expressed in this paper are entirely those of the authors. They do not necessarily represent the views of the International Bank for Reconstruction and Development/World Bank and its affiliated organizations, or those of the Executive Directors of the World Bank or the governments they represent.

a. World Bank, e-mail: crodriguezc@worldbank.org.

b. Center for Distributive, Labor, and Social Studies, Instituto de Investigaciones Económicas, Facultad de Ciencias Económicas, Universidad Nacional de La Plata, e-mail: evazquez@cedlas.org.

c. World Bank, e-mail: hwinkler@worldbank.org.
# **1. Introduction**

Despite the large theoretical and empirical literature documenting that access to international trade can be beneficial for economic development (Edwards 1993; Goldberg and Pavcnik 2016; Wacziarg and Welch 2008), there has been a rise in protectionism in discourse and measures around the world recently (Donnan 2016). This trend is also reflected in the perceptions of individuals on trade. Pavcnik (2017) shows that the share of people reporting that trade is beneficial to the economy has declined since 2002.

Consistent with these trends, recent empirical evidence points to the negative impact import competition from developing countries had on workers in developed economies (for example, see Autor, Dorn, and Hanson 2013; Balsvik, Jensen, and Salvanes 2015; Hakobyan and McLaren 2016). Meanwhile, standard trade models predict that a rise in exports from developing to developed nations would benefit workers in countries with abundant labor. In fact, recent studies show a substantial impact of exports on poverty reduction and improved labor market outcomes at the local level in China and Vietnam (Erten and Leight 2019; McCaig 2011, McCaig and Pavcnik 2018) and on poverty and inequality among states in Brazil (Castilho, Menéndez, and Sztulman 2012). Yet other empirical studies find contrasting results, including that trade liberalization does not necessarily benefit all households in developing countries and may lead to widening inequality and declining labor market outcomes (De Loecker et al. 2016; Dix-Carneiro and Kovak 2017; Erten, Leight and Tregenna 2019; Goldberg and Pavcnik 2007; Nicita 2009; Pavcnik 2017; Revenga 1997; Topalova 2010). The underlying channels through which international trade may or may not benefit individuals and regions in developing countries are not fully understood.

This paper investigates the effects of a rise in exports on poverty and inequality using a rich municipality-level data set from a developing country. Mexico is an interesting case given its lackluster performance in economic growth and poverty reduction, despite a significant trade expansion (Hanson 2010). Mexico joined the forerunner of the World Trade Organization, the General Agreement on Tariffs and Trade, in 1986 and the North American Free Trade Agreement (NAFTA) in 1994, leading to substantial tariff reductions globally and regionally, greater export orientation, and diversification away from oil. Exports as a share of gross domestic product (GDP) rose by 20 percentage points beginning in 1994, following reforms to open the economy to trade and to liberalize domestic markets. Most of Mexico’s exports— 2
about 70 to 80 percent since 2004—go to one high-income economy, the United States. Yet, Mexico has underperformed in terms of growth, inclusion, and poverty reduction relative to its peers (World Bank 2019), and there has been only limited income and poverty convergence across municipalities (López-Calva, Ortiz-Juárez, and Rodríguez-Castelán 2019).<sup>1</sup> That increasing exports did not translate into lower poverty and higher income growth is not yet fully understood. Lederman, Maloney, and Servén (2005) argue that NAFTA had positive impacts on foreign direct investment (FDI), trade, and productivity in Mexico, but only modest impacts on wages and the convergence of income per capita. Rodríguez-Castelán, LópezCalva and Barriga (2020) find that local exposure to trade is associated with higher productivity in the manufacturing sector which in turn declines with higher industry concentration. Accordingly, suggestive research points out that negative aggregate shocks in Mexico tend to have important negative effects in regional growth, but that positive shocks, such as a rise in export growth, are not typically reflected in large positive effects on growth nor, to a certain extent, on household welfare. In most states in Mexico between 2005 and 2014, as Campos-Vázquez and Monroy-Gómez-Franco (2016) observe, negative shocks increased poverty more than positive shocks reduced it. The dynamics behind this observation is, up to a point, what this paper aims to test, that is, to identify how and whether a positive trade shock—growth in exports—benefits (or not) the population at the local level.

The scarce research on the impact of export growth on wages and employment in Mexico tends to concentrate on studies on plants or firms (Frías, Kaplan, and Verhoogen 2012; Verhoogen 2008), industry (Waldkirch, Nunnenkamp, and Bremont 2009), or regions (Airola 2008; Chiquiar 2008; Feenstra and Hanson 1997). Within this research, there is some evidence of an equalizing effect of trade on wages that is consistent with the Heckscher–Ohlin model. Chiquiar (2008) finds that regions exposed to NAFTA show an increase in wage levels, but a decrease in the skill premium, and Airola (2008) finds that the wage skill premium is negatively related to maquiladora employment (used as a proxy for FDI). There is also evidence of a small but positive impact of FDI on manufacturing employment (Waldkirch, Nunnenkamp, and Bremont 2009). Meanwhile, there is evidence pointing to a connection

> 1 Between 2004 and 2014, poverty declined in Mexico by 4.0 percentage points, from 37.6 to 33.6 percent, while, in Latin America and the Caribbean, it declined by nearly 17.0 percentage points, from 41.3 to 24.4 percent (US$5.50-a-day per capita poverty line in 2011 purchasing power parity). Moreover, almost half the decline in poverty in Mexico is explained by redistribution (because of the shift from general subsidies to targeted and conditional transfers) rather than to economic growth, despite the expansion in trade over the period. In Latin America, in contrast, redistribution only explains about 20.0 percent of the decline, while economic growth accounted for nearly 80.0 percent of the reduction in poverty.

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between trade and wage inequality (Frías, Kaplan, and Verhoogen 2012; Verhoogen 2008), as well as a link between FDI and a rise in the share of skilled labor in total wages (Feenstra and Hanson 1997). Hanson (2007) explores the distributional impacts of NAFTA and finds that Mexican regions more highly exposed to the agreement witnessed a larger decline in poverty and inequality. Prina (2013, 2015) finds that the change in prices of agricultural exports associated with NAFTA benefited small farmers more than large farmers. She also finds that agricultural wages did not change, but employment grew in sectors that had experienced a price increase. None of these studies, however, identifies the causal impact of the overall increase in exports experienced by Mexico on local household incomes.

This paper contributes to the literature by exploiting variations in export growth across Mexican municipalities between 2004 and 2014 to identify the impacts on poverty, inequality, and household incomes across the distribution. It finds that the effects of exports on household incomes tend to be progressive because they tend to be positive only among the poorest deciles. Nonetheless, these results are not robust to alternative specifications. To understand what is behind such weak impacts of rising exports on incomes, the paper investigates labor market mechanisms. It finds that, while exports do raise the total amount of labor income at the municipal level, average labor incomes do not change. This is because municipalities experiencing growing exports also experience an increase in labor supply that is driven by rising labor force participation, inflows of returning migrants, and lower emigration outflows. These results are consistent with the hypothesis put forward by Robertson (2007), who argues that the lack of positive labor market impacts of trade integration may be partly explained by migration. In addition, the paper finds that remittances tend to decline more in municipalities experiencing higher export growth.

This paper contributes to the literature in several ways. It is the first study to focus on the role of exports at the local level in a developing country using unique panel data from poverty maps, combined with data on exports at the municipal level. Second, it uses an instrumental variable that allows the causal impact of exports to be disentangled. The instrument combines the initial export structure by sector at the municipal level with global trends in exports from developing to developed countries by sector. Municipal-level trends in this instrument are thus not affected by local-level shocks. Third, it provides new evidence on the channels that could help explain why increasing exports may not necessarily translate into higher income growth 4
and poverty reduction. This appears to be the first study to show that migration and remittances mitigate the impacts of exports on incomes and poverty at the local level in Mexico.<sup>2</sup> The rest of this paper is structured as follows. Section 2 presents the identification strategy. Section 3 describes the data sources. Section 4 presents the findings, and section 5 concludes.

# **2. Identification Strategy**

An equation is estimated as follows: 0 , (1) mm,tt mm,tt−ττ mm,tt mm,tt−ττ mm,tt mm,tt,tt−ττ yy −yy = αα+ ββ�xx −xx �+ΓXX + εε where is the poverty headcount ratio or income distribution measure in municipality _m_ and year mm,tt _t_ . 0 is a vector of variables to control for different trends across municipalities. yy These include literacy rate, sectoral structure of employment, total population, and the share mm,tt XX of the population in rural areas in the baseline year 0. The change in the main variable of interest, , is as follows: tt mm,tt xx ln e e <u>,</u> e e <u>,</u> , (2) ~~� �~~ −ln � ~~�~~ eetteemm tt eetteemm tt−ττ wwe wwe eemm,0 wwe wwe eemm,0 where represents yearly exports originating from municipality _m_ , and is the number of workers ages 12 or more in municipality mm,tt _m_ in the year 2000. This variable is mm,0 eexxe eettee wwe wwe ee introduced in logarithms to limit the weight of extreme values because it is highly skewed toward the left. As seen in figure 1, the distribution of this variable becomes more symmetric (in both levels and first-differences) if logs are used. In addition, to prevent losing municipalities from the sample that have zero exports in one or both years because of the logarithmic transformation, a constant equal to 1 is added to the exports per worker variable so that this is never zero.

Ordinary least squares (OLS) estimates of may be biased if there are omitted variables correlated both with household incomes and exports. More specifically, more prosperous areas ββ with higher income growth and poverty reduction rates would be more likely to attract FDI and thereby become export hubs. This would tend to lead to OLS estimates that are upward biased. However, if policy incentives encourage exporting firms to locate in poorer areas, then

> 2 Majlesi and Narciso (2018) find that Mexican municipalities that are more highly exposed to Chinese import competition exhibit higher out-migration to other municipalities, but less out-migration to the United States.

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# **3. Data and Descriptive Statistics**

# **3.1.Data**

Different data sources are used on trade, incomes, labor market outcomes, and migration at the municipal level. First, the data on exports by municipality, year, and sector supplied by the tax authority of Mexico (Servicio de Administración Tributaria) cover each municipality in 2004– 14. Data are reported using the 2002 Harmonized System classification at the 4-digit level and converted to the International Standard Industrial Classification (Revision 4) classification using correspondence tables.<sup>4</sup> The poverty headcount ratios, Gini coefficients, and mean incomes by decile at the municipal level have been estimated using the poverty mapping methodology (Elbers, Lanjouw, and Lanjouw 2003). The data are available for 2000, 2005,

> 3 For example, Autor, Dorn, and Hanson (2013) estimate the impacts of import competition from China on local US labor markets by combining the initial local distribution of employment across sectors and nationwide changes in imports from China by sector. They instrument this variable using changes in Chinese imports by other highincome countries.

> 4 See UNDESA (2008); HS (Harmonized Commodity Description and Coding Systems) (database), Statistics Division, Department of Economic and Social Affairs, United Nations, New York, https://unstats.un.org/unsd/tradekb/Knowledgebase/50018/Harmonized-Commodity-Description-and-CodingSystems-HS.

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2010, and 2015. The 2005 and 2015 data have been used because they match more closely the end-point years of the trade data. (See Enamorado et al. [2016] for a detailed description of the data.) For labor market and migration indicators, tabulations from the 2000 and 2010 Census of Population and Housing and the 2015 Population Count are used to obtain labor market indicators, as well as information on the demographic characteristics of the population at the municipal level.<sup>5</sup> Given that publicly available data from the Mexican Institute of Statistics do not allow for more than two cross-tabulations, the census microdata samples of the Integrated Public Use Microdata Series are used to estimate labor market indicators on more detailed groups (Ruggles et al. 2007). Because the 2005 data do not include detailed information on labor market outcomes, 2000 data are used instead as the initial year for these indicators. The analysis also relies on the absolute index of migratory intensity between Mexico and the United States in 2000–10 to capture emigration and immigration with respect to the United States, as well as the remittances received in Mexico from that country (CONAPO 2014). The analysis uses the exports from developing to developed countries at the 2-digit level from the BACI international trade database to construct the instrumental variable (Gaulier and Zignago 2010).<sup>6</sup> Low- and middle-income countries are defined as developing economies, and highincome countries are defined as developed, following the World Bank’s income classification.

# **3.2. Descriptive Statistics**

Mexico has experienced a substantial increase in exports since the 1990s (figure 2). Exports of goods and services increased from US$96.7 billion to US$480.0 billion in 1990–2018. As a share of GDP, the rise was from 18.7 to 39.2 percent. This analysis focuses on 2004–14 because the municipal-level export data set only covers those years. While this excludes the initial period of NAFTA, it still captures a significant increase in exports, from about 28.4 percent to about 31.9 percent of GDP.

According to various measures, poverty declined almost every year, with the main exception of the 1994–95 tequila crisis (figure 3). This is particularly true of the US$3.20-a-day and

> 5 Even though the 2015 population count is from a survey, the sample size is sufficiently large to provide statistics representative at the municipality level. See Enamorado et al. (2016).

> 6 These include the following sectors: agriculture, mining, food products, textiles, wood, paper, printing, chemicals, rubber and plastics, metal, electronics, machinery, automotive, other manufacturing, utilities, construction, education, and other nonmanufacturing.

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US$1.90-a-day poverty lines. Moderate poverty showed a smaller decline, from about 44 to 34 percentage points in 1992–2006 and has remained stagnant since then. Nonetheless, these declines are relatively small compared with those in other countries typically mentioned as examples of successful export-led growth. For example, while the share of exports in GDP in Vietnam rose from 54.7 to 70.3 percentage points in 2002–08, the share of people living on less than US$3.20-a-day declined from about 70.8 to 46.8 percentage points. Measured according to the US$1.90-a-day poverty line, the decline was also large, from about 38.0 to 14.8 percentage points.<sup>7</sup> Table 1 shows descriptive statistics on the sample used in the estimations. The focus is on urban and semiurban areas (1,982 of 2,457 municipalities), given that these areas represent more than 99 percent of total exports over 2004–14 and two-thirds of rural municipalities show zero or close to zero exports. Municipalities with a higher ratio of exports per worker exhibit a lower incidence of poverty and higher incomes (figure 4). Income inequality is similar across these two groups of municipalities, with a Gini coefficient of about 0.38 or 0.39. Moreover, a simple inequality decomposition of the Theil index shows that within-municipality inequality accounts for about three-quarters of total inequality in Mexico. Understanding the role of trade in shaping inequality at the local level in Mexico is thus relevant because trade explains most of the inequality at the national level.

# **4. Results**

# **4.1.Poverty and Income**

Table 2 shows the estimates of equation 1 using the share of the extreme poor as the dependent variable. The preferred specification is in column (3), which controls for the share of the rural population, the literacy rate, total population, and the shares of workers by sector as well as median income per capita in 2000 to account for different trends in trade and labor market outcomes along these dimensions. Illustrated in columns 1–3, exports per worker are negatively correlated with poverty at the municipal level. The results are statistically

> 7 For the export data, see “Exports of Goods and Services (% of GDP): Vietnam,” World Bank, Washington, DC, https://data.worldbank.org/indicator/NE.EXP.GNFS.ZS?end=2018&locations=VN&start=1986. For the poverty data, see Poverty and Equity Data Portal: Vietnam (database), World Bank, Washington, DC, http://povertydata.worldbank.org/poverty/country/VNM. The US$5.50-a-day poverty line is not a good reference point for comparing Mexico and Vietnam because, during this period, the vast majority of Vietnamese households were poor according to this definition.

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significant, but small in magnitude. In particular, a 10 percent rise in exports per worker is associated with a 0.034 (column 3) to 0.039 (column 1) percentage point decline in poverty.<sup>8</sup> Because OLS estimates may be biased if unobserved shocks at the local level are correlated with both exports and income levels, the analysis adopts an instrumental variable approach. The results of the first-stage regressions are displayed in table 3 and indicate that the instrument is highly correlated with the endogenous variable: the F-statistic surpasses the standard significance threshold. Figure 5 shows that the association between the instrument and the endogenous variable is strong.

In table 2, columns 4–6 show the instrumental variable estimates of the impacts on extreme poverty. Exports do not lead to lower poverty rates at the municipal level. According to the preferred specification in column 6, a 10 percent rise in exports per worker reduces the poverty headcount ratio by 0.17 percentage point, a magnitude that is statistically indistinguishable from zero. The impact is negligible considering that the exports-to-worker ratio increased by 12.3 percent during the period under analysis and that the extreme poverty rate was 37 percent in 2005.

Table 4 shows that the rise in household incomes per capita led by export growth in urban and semiurban areas was experienced solely at the bottom of the income distribution. Export growth led to higher income growth among households in the two poorest deciles in urban areas. This explains why no impacts are found in poverty rates; the extreme poverty line corresponds to the income levels of households in the third decile. A 10-percent increase in exports per worker raised average incomes per capita by about 0.86 and 0.60 percent in the first and second deciles, respectively. The magnitude of the coefficients declines gradually as one ascends the income distribution. As a result, the estimates imply that exports tend to reduce income inequality at the local level. In particular, the Gini index falls by around 0.17 point (using a 0–100 scale) if the exports-to-worker ratio rises by 10 percent (table 5, column 6). This is a significant change, considering that the Gini index declined 0.17 point (from 38.6 to 38.43) in 2005–15 (table 1) and that, according to the estimates, three-quarters of Mexico’s income inequality is explained by within-municipality inequality.

> 8 In a lin-log model, to calculate the expected change in the dependent variable associated with a 10 percent rise in the independent variable, the estimated coefficient should be multiplied by log(110/100) = log(1.1) = .095.

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That exports exert a progressive impact on incomes at the local level contrasts with the findings of plant-level studies documenting the unequalizing impacts on wages in Mexico. For example, Frías, Kaplan, and Verhoogen (2012) find that exports raise within-plant wage inequality, and Verhoogen (2008) finds that they increase within-industry wage inequality. However, the results of the analysis are broadly in line with the findings of the literature exploiting regional variations in exports and labor market outcomes (Airola 2008; Chiquiar 2008; Hanson 2007).

Table 6 illustrates a robustness check of the main results by controlling for the initial characteristics of municipalities. The impact of exports on the average income of the poorest decile is sensitive to the inclusion of this additional set of controls: the estimated coefficient becomes statistically insignificant if one controls for the sectoral composition of employment and exports. However, the impacts of exports on relative incomes continues to be statistically significant and progressive across all specifications, as shown by the effects on the Gini coefficient.

To understand the impacts of exports on the income distribution more precisely, the following subsections examine two mechanisms that may help explain why any potential gains in exports are not reflected in higher household incomes per capita and less poverty.

# **4.2. Labor Market Impacts**

Table 7 shows the impact of exports on the labor market. The estimates indicate that exports tend to increase labor force participation (panel a). In particular, a 10 percent increase in exports per worker raised the share of working-age individuals working or looking for a job by 0.15 percentage point (column 6). The economic significance of this impact is rather small, considering that the labor force participation rate in the average municipality in 2000 was 45.8 percentage points.

The OLS results suggest that exports per worker and employment rates are strongly associated, although the economic significance is small (panel b). In particular, a 1 percent rise in exports per worker is associated with an increase of 0.05 percentage point in the local employment rate, which represents only 0.11 percent of the employment rate of the average municipality in 2005. The instrumental variable estimates are less precise than the OLS estimates. The only statistically significant result is in the specification without any control variables, which shows 10
that a 10 percent increase in exports raised employment rates by 0.23 percentage point on average.

The weak employment impacts may be explained by the fact that exports led to a labor supply shock by raising the number of net migrants, thereby increasing both the numerator and the denominator of the employment rate. The analysis investigates this issue by examining the impacts on total labor incomes, that is, the sum of all labor incomes in the municipality. The impacts of exports on total labor income at the local level are statistically significant. A 10 percent rise in exports per worker raised total labor incomes by 2.4 percent on average (panel c, column 6). This is significant in economic terms as well, considering that total labor incomes in real terms grew by 9.2 percent during the period. Despite the increase in total labor incomes, labor income per worker did not rise in response to export growth. The OLS and IV effects are not statistically significant (panel d).

# **4.3. Migration and Remittances**

The period under analysis includes the financial crisis (2008–09), that is, the first year in which the stock of Mexican migrants to the United States started to decline because of a lower number of arrivals to the United States and a higher number of Mexican returnees. The number of unauthorized migrants from Mexico to the United States fell from the peak of 6.9 million in 2007 to 5.6 million in 2015 (Gonzalez-Barrera and Krogstad 2019). The total stock of people born in Mexico and living in the United States fell from about 11.7 million to 11.2 million in 2010–18.<sup>9</sup> Local exports played an important role in determining which municipalities were less likely to send emigrants to the United States and which ones were more likely to absorb returnees. Internal migration flows were also responsive to changes in local exports.

Table 8 shows the impacts of exports on migration. A 10 percent rise in exports per worker raised the number of people who had migrated in the previous five years to the municipality by about 7.1 people (panel a, column 1). This represents about 4.6 percent of the number of recent migrants for the average municipality in 2005. Most of this immigration response was generated by internal migrants (panel b). Indeed, a 10 percent increase in exports per worker raised the number of immigrants from other Mexican municipalities by about 4.9 people. The corresponding estimate for external migrants was only 2.2 people (panel c). The inflows of

> 9 See “U.S. Immigration Trends,” Migration Policy Institute, Washington, DC, https://www.migrationpolicy.org/programs/data-hub/us-immigration-trends#source.

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migrants were larger among the unskilled. A 10 percent rise in exports per worker raised the number of unskilled migrants by 5.2 people (panel a, columns 2–4). In contrast, the increase in the number of middle skilled and highly skilled migrants was only a fifth or less.

Table 9 shows the impacts among returnees from and emigrants to the United States in 2000– 10.<sup>10</sup> A rise in exports per worker by 10 percent raises the number of households with returning migrants from the United States by 14 on average. At the same time, it reduces the number of households with emigrants to the United States by about 9.

These internal and external patterns of migration also help explain the increase in the size of the working-age population experienced by municipalities when exports are growing. The size of the total population ages 14–55 in urban municipalities rose, especially among the unskilled, in response to export growth (table 8, panel d). While the size of the skilled working-age population increased by about 11.6 people when exports per worker rose by 10 percent in the average municipality, the size of the unskilled working-age population increased by about 82.1 people. This represents about 30 percent of the increase in the number of unskilled people in this age-group in the average municipality during the period. The migration response to higher exports implies that the estimated positive impacts on the local labor market are partially diluted because of the increase in the size of the local working-age population, particularly the unskilled.

A 10 percent increase in the growth of the export-to-worker ratio reduces the share of households receiving remittances from the United States by 0.18 percentage point (table 9, column 3). This represents almost 1.4 times the decline in the share of households receiving remittances during the period. This may be explained by the fact that the number of household workers abroad falls disproportionately as exports grow. An additional consumptionsmoothing mechanism may be important if, for example, more job opportunities reduce the need to rely on remittances.

# **5. Conclusion**

This paper provides new evidence on the impacts of exports on welfare in developing countries. Using a rich data set on exports, income distribution, labor market outcomes, and migration at the municipal level in Mexico in 2004–14, it offers new insights on why a

> 10 These data are not available for 2005 and 2015.

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significant growth in exports does not necessarily lead to better average welfare indicators at the local level.

Although the analysis finds that raising exports may reduce income inequality, there is no evidence of significant effects on poverty and average household incomes. This is because while growth in exports leads to higher total labor income, it also raises the supply of labor through inflows of migrants, particularly unskilled ones. Internal and external migration flows thus offset somewhat the positive impacts of exports for the average resident at the local level. Remittances also tend to decline in response to rising exports.

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