Long and Short Distance Migration in Italy: The Role of Economic, Social and Environmental Characteristics

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1 Spatial Economic Analysis ISSN: (Print) (Online) Journal homepage: Long and Short Distance Migration in Italy: The Role of Economic, Social and Environmental Characteristics Bianca Biagi, Alessandra Faggian & Philip McCann To cite this article: Bianca Biagi, Alessandra Faggian & Philip McCann (2011) Long and Short Distance Migration in Italy: The Role of Economic, Social and Environmental Characteristics, Spatial Economic Analysis, 6:1, , DOI: / To link to this article: Published online: 28 Jan Submit your article to this journal Article views: 2181 View related articles Citing articles: 46 View citing articles Full Terms & Conditions of access and use can be found at Download by: [ ] Date: 17 November 2017, At: 13:01

2 Spatial Economic Analysis, Vol. 6, No. 1, March 2011 Long and Short Distance Migration in Italy: The Role of Economic, Social and Environmental Characteristics BIANCA BIAGI, ALESSANDRA FAGGIAN & PHILIP McCANN (Received June 2010; accepted November 2010) ABSTRACT This paper analyses Italian interregional migration flows. The approach taken is to decompose labour mobility flows into short distance and long distance migration and to model the effects of economic variables, social capital and quality of life variables, and amenity variables, on the mobility behaviour of individuals. We estimate these different types of migration flows using a negative binomial model, augmented with instruments to control for potential endogeneity issues. Our findings demonstrate that long distance migration reflects a disequilibrium model of migration whereas short distance migration largely reflects an equilibrium model of migration. As such, attempts to model interregional migration in general will be mis-specified as the simultaneously-operating underlying mobility systems are quite different in nature. Migration éloignée et rapprochée en Italie : rôle de facteurs économiques, sociaux et environnementaux RÉSUMÉ La présente communication analyse les flux migratoires interrégionaux en Italie. Le principe adopté consiste à décomposer les flux de mobilité de la main-d œuvre en migrations rapprochée et migration éloignée, puis de modéliser les effets de variables économiques, de variables propres au capital social et à la qualité de vie, et de variables sur le plan de l agrément sur le comportement de la mobilité des particuliers. Nous effectuons une estimation de ces différents types de flux migratoires en utilisant un modèle binomial négatif, renforcé par des instruments pour le contrôle de questions d endogénéité potentielles. Nos conclusions démontrent que la migration éloignée reflète un modèle de déséquilibre de la migration, alors que la migration rapprochée reflète en grand partie un modèle déséquilibre de la migration. De cette façon, toutes tentatives de modélisation de migrations interrégionales seront spécifiées de façon erronée, du fait de la nature différente des systèmes de mobilité sous-jacents agissant simultanément. Bianca Biagi (to whom correspondence should be sent), Centre for North South Economic Research (CRENoS) and Department of Economics (DEIR), University of Sassari, Sassari, Italy. bbiagi@uniss.it. Alessandra Faggian, School of Geography, University of Southampton, Highfield, Southampton SO17 1BJ, UK. a.faggian@soton.ac.uk. Philip McCann, Spatial Sciences, University of Groningen, Groningen, Netherlands. P.McCann@rug.nl ISSN print; online/11/ # 2011 Regional Studies Association DOI: /

3 112 B. Biagi et al. La migración de larga y corta distancia en Italia: el papel de las características económicas, sociales y ambientales RESUMEN En este trabajo se analizan los flujos migratorios interregionales de Italia. El método adoptado es la descomposición de los flujos de movilidad laboral en migración de corta y migración de larga distancia, y modelar los efectos de las variables económicas, las variables de capital social y de calidad de vida, y las variables de bienestar, con base en el comportamiento de la movilidad de los individuos. Estimamos estos tipos de flujos migratorios diferentes a través de un modelo binomial negativo, ampliado con instrumentos que permiten controlar los posibles problemas de endogeneidad. Nuestras conclusiones demuestran que la migración de larga distancia refleja un modelo desequilibrado de migración, mientras que la migración de corta distancia refleja en gran medida un modelo equilibrado de migración. Como tal, los intentos para modelar la migración interregional, en términos generales, serán tergiversados dado que los sistemas de movilidad subyacentes que funcionan simultáneamente son de naturaleza bastante diferente. KEYWORDS: Interregional; endogeneity; amenities; social capital; migration; disequilibrium JEL CLASSIFICATION: J61; R1; R11; R23 1. Introduction The factors which determine interregional migration flows are both complex and also hotly debated. In the 1980s two main traditions of migration studies emerged. On one side, in keeping with the original observation by Hicks (1932) who stated that differences in net economic advantages, chiefly differences in wages, are the main cause of migration, the so-called disequilibrium model of migration (Muth, 1971; Greenwood, 1975, 1985; Greenwood & Hunt, 1984) treated interregional migration almost entirely as an economic phenomenon and a by product of employment search. People react to initial disequilibria in wages and unemployment by moving to areas where the level of wages is higher, while unemployment is lower eventually restoring equilibrium over space. Two main shortcomings of the disequilibrium approach, however, became immediately apparent. Firstly, while the model predicted convergence among regions, regional disparities were quite persistent over time casting doubt on the role of migration as a re-equilibrating mechanism. Secondly, the empirical implementations of the model found an embarrassing number of unhypothesized signs, with people migrating in large numbers to areas of low income and to highunemployment destinations (Knapp & Graves, 1989).

4 Long and Short Distance Migration in Italy 113 The equilibrium approach of migration, mainly linked to the work of Graves (1976, 1980, 1983), proposed an alternative view of interregional migration which explained the reasons underlining the unexpected relationship between migration and real wages. In this new view, differences in wages are partially compensating for spatial variations in non-tradable non-economic factors. Graves (1980) focused specifically on location-specific natural amenities such as climate and temperature, but, building on his initial intuition, other analysts started to consider other humanproduced amenities including public services (Blomquist et al., 1988; Gyourko & Tracey, 1991) and social, cultural and skill-dependent amenities (Glaeser et al., 2001; Florida, 2002) which appear to be particularly important in an urban context (Shapiro, 2006). Although these approaches were seen as antagonistic at the beginning, and produced an intense debate (Schachter & Althaus, 1989; Evans, 1990, 1993; Harrigan & McGregor, 1993; Graves & Mueser, 1993), it became clear over time that, in fact, they are not irreconcilable (see Faggian & Royuela, 2010). In migrating, people compare utility differentials across different alternative locations and these utility differentials are a function of both economic and non-economic (quality of life) factors. The main point is the relative weight of these factors. Economic and non-economic factors might be given a different weight by people in different countries or, even within a given country, by people in different circumstances (e.g. with different income level). The latest US evidence suggests that non-economic factors such as natural amenities (Partridge & Rickman, 2003, 2006; Partridge, 2010) are a key driver in influencing migration patterns and that the growth of cities is also very dependent on the migration induced by spatial sorting by skills and the interactions between these skills and the consumption of urban amenities (Glaeser et al., 2001; Adamson et al., 2004; Shapiro, 2006). In Europe, however, the situation seems rather different. It is well known that European countries generally exhibit much lower levels of interregional migration than the US, but the differences are not simply in terms of degrees of mobility. The vast majority of evidence from Europe suggests that interregional migration is primarily driven by a disequilibrium mechanism in which, allowing for life-cycle effects (Fielding, 1993), migration is mainly a response, albeit slow, to spatial differences in economic factors such as wages and employment opportunities (Faggian & McCann, 2009a). Natural amenities, such as climate, do not affect migration to the extent found in the US (Cheshire & Magrini, 2006). Ferguson et al. (2007) reach similar conclusions for Canada. It is likely that the transatlantic differences in the scale of the interregional migration processes are due to the much greater institutional, cultural, historical and linguistic variations across space in Europe than in North America. This greater heterogeneity between European countries might also affect the different weights given to economic vs. non-economic factors in the decision to migrate. People in Europe do not migrate with the same frequency as in the US, but when they do they seem to do so in response to economic needs rather than quality of life choices and this is even more evident when the economic and labour market disparities between the origin and destination are greater. Surprisingly, the difference in the weights given to economic and noneconomic factors in considering utility differentials might also hold within a given

5 114 B. Biagi et al. country. In the case of Italy, for instance, the dynamics of long distance migration between the poorer south and the richer north seem quite different than the dynamics regulating shorter distance migration patterns between relatively close cities. The main aim of this paper is to investigate these differences between long distance and short distance migration within Italy. In order to do so we employ a uniquely detailed set of inter-provincial migration data within an empirical framework which incorporates a variety of economic factors, location-specific amenities, together with social and cultural capital variables. Such a detailed analysis has not been done before for the Italian case. Most migration research in Italy has examined interregional flows among larger areas, either regions or groups of regions, and has not examined the differences in the determinants of movements of different lengths (Attanasio & Padoa-Schioppa, 1991; Faini et al., 1997; Daveri & Faini, 1999; Cannari et al., 2000; Furceri, 2006; Basile & Causi, 2007; Etzo, 2008). The paper is structured as follow. Section 2 provides a brief theoretical discussion and explanation of the model. Section 3 explains some of the major observed features of interregional migration in Italy. Section 4 discusses the empirical methodology and the data at our disposal. Section 5 reports the results and finally Section 6 provides some conclusions. 2. Theoretical Framework and Empirical Methodology Our model is based on the very well-know utility maximizing framework. Assuming that individuals are rational and they are freely mobile, their decision to move from one location to an alternative one will be based on a comparison between the expected utilities of the two locations. We assume that the individual utility is a function of economic variables, location-specific non-tradable amenities and the costs of moving which are approximated by distance. Hence, the utility of the i-th location for the k-th individual can be formally expressed as: U k i u(a i ; E i )o k i (1) where the total utility U includes a deterministic part u and a stochastic part o k i : The deterministic part u is, in turn, a function of a vector of a wide range of amenities (A i )*not only natural but also man-made*and a vector of economic variables (E i ). An individual will decide to migrate from location i (origin) to location j (destination) if the expected utility on the destination is greater than the expected utility at the origin plus the costs of relocating (which are a function of distance): (EU k j )(EU k i )C(d ij) (2) When condition (2) is satisfied, then we define a variable Mji k being equal to 1 (0 otherwise). By aggregating individual movements by province (103 in Italy 1 ) and employing a very general gravity-type model specification, we can write: M ij f (DE ij ; DA ij D ij ) (3) where: i1, 2,..., 103; j1, 2,..., 103 (with j"i); Evector of economic characteristics of the origin i and destination j; Avector of social and environmental characteristics of the origin i and destination j; and D ij distance between i and j.

6 Long and Short Distance Migration in Italy 115 The dependent variable is the gross migration from province i to province j. D ij represents the linear distance in kilometres among the centroids of the provinces (Etzo, 2008), and as such, our model can be considered to be somewhat in the spirit of the gravity-employment model of Lowry (1966). As our dependent variable is gross migration flows and it is therefore represented by integer numbers, we required the use of count-data models. 2 The most popular specification of count data is the Poisson model: f y (y; m)e m + m y! (4) where y is a strictly non-negative number representing the number of occurrences (the dependent variable) and m is the expected number of occurrences often called intensity or rate parameter. As there is only one parameter in the Poisson distribution, the equality between the mean and the variance is assumed (equidispersion): m i exp(x i b)e[y i jx i ]Var[y i jx i ] (5) where x is the vector of explanatory variables. The use of a Poisson distribution in modelling residential flows is not new in the migration literature (among others Congdon, 1989; Mueser, 1989; Boyle & Halfacree, 1995). However, the equidispersion assumption is a serious limitation of the Poisson model as, more often than not, real data exhibit overdispersion, i.e. a variance greater than the mean. When this happens the conventional Poisson model produces serious biases in the parameter estimates (Cameron & Trivedi, 2005). A simple investigation of our dependent variable (Table 1) shows that our data are indeed overdispersed. Overdispersion is further confirmed by the z-test and the Lagrange multiplier test or score test (Winkelmann, 2008) performed after running the first Poisson model. 3 The traditional way to deal with overdispersion is to use mixture models. These models explicitly model heterogeneity among observations by adding an extra parameter, which is a function of unobserved heterogeneity. In other words the mean in Equation (5) is replaced by: m i exp(x i b)exp(o i ) (6) The negative binomial model is a specific case of mixture models in which exp(o i ) is supposed to be drawn from a gamma distribution so that the probability density is: Table 1. Gross flows summary statistics Observations 10,506 Mean SD Variance 20, Skewness Kurtosis Percentile Smallest 1% 0 0 5% % % % 12 0 Largest 75% 31 2,575 90% 88 3,244

7 116 B. Biagi et al. Pr(yM x) G(y a1 ) a 1 y!g(a 1 ) a 1 m a 1 m y (7) a 1 m where G indicates the standard gamma function and a (called ancillary parameter ) determines the degree of dispersion in the predictions (the larger a, the more spread are the data). If a 0, the binomial negative model reduces to the Poisson regression model. The negative binomial model is nonlinear and is normally estimated using the maximum likelihood NewtonRaphson algorithm. The use of the negative binomial to model migration flows is relatively recent in the literature (see also Devillanova & Garcìa Fontes, 2004). In this paper we follow the approach of Hilbe (2007) in which, as in the majority of studies, the negative binomial model is considered as a derivation of a Poissongamma mixture model with two parameters to be estimated (a and m), but it is also considered as a member of a single parameter exponential family distribution, such as generalized linear models (GLMs). This is possible only if the heterogeneity parameter is held as constant in the model. This solution allows us to apply the goodness-of-fit tests and residual analysis already used for generalized linear models to the negative binomial model. In this case the estimation uses Fisher-scores based on an iteratively reweighted least square algorithm. 3. Data Our data come from the Movimento migratorio della popolazione residente*iscrizioni e cancellazioni anagrafiche (Migratory movements of resident population*registrations and cancellations to the registry office) by the Italian National Institute of Statistic (ISTAT, 2006) for the years 2001 and Our dependent variable was built using the matrix of inter-provincial movements. Given that the matrix has a dimension of , and excluding the diagonal which contains only zeros by construction, we have a total of 10,506 observations on gross migration flows. Table 2 gives a description of the variables used in the empirical analysis. The independent variables are divided into seven main categories: spatial, economic, demographic, human capital, social capital, amenity and quality of life variables. Except for the dummies and the distance, all other variables are expressed in terms of difference between the values at destination and origin. The literature on migration widely recognizes the key role of space in migration processes (Greenwood, 1997; Cushing & Poot, 2004; LeSage & Pace, 2008). The spatial interaction models developed in this paper control for the negative effect of space using the geographic distance between provinces; distance is also used as a proxy for the general cost of moving (Juarez, 2000). The effect of economic disparities are tested using GDP per capita and unemployment rate, even though the extended version of the gravity model à la Lowry (1966) employs wages and unemployment rate. Data on average wages and GDP are very difficult to find since the Italian National Statistic Institute (ISTAT) does not calculate them at the provincial level. Fortunately, provincial GDP per capita is provided by the Guglielmo Tagliacarne Institute (see Table 2). It is worth noting that GDP is often used in gravity models (Congdon, 1989; Shen, 1999; Devillanova & Garcìa Fontes, 2004) and, as in previous research, we expect that the higher the GDP in the destination, the higher the in-migration and the lower

8 Table 2. Model variables and summary statistics Definition Mean SD Distance Linear distance in kilometres between the centroids of the provinces Economic variables GDP GDP per capita at current prices. Year Source: our elaboration on Guglielmo Tagliacarne Institute 16, , Unemployment Unemployment rates (people looking for a job/labor force)*100. Year Source: our elaboration on ISTAT, Sistema di Indicatori Territoriali (downloaded April 2009) Demographic variables Population Total population. Year Source: ISTAT, Sistema di Indicatori Territoriali (downloaded 21 luglio 2008) 559, , Age 2039 Percentage of people of age between 20 years old and 39 over the total population. Year Source: our elaboration on ISTAT, Atlante Statistico dei Comuni Age 4064 Percentage of people of age between 40 years old and 64 over the total population. Year Source: our elaboration on ISTAT, Atlante Statistico dei Comuni Age 65 Percentage of people of age 65 years old and more over the total population. Year Source: our elaboration on ISTAT, Atlante Statistico dei Comuni Human capital Diploma People with Italian diploma per 10,000 inhabitants. Year Source: our elaboration on ISTAT, Atlante Statistico dei Comuni 1, Social capital Sport Individuals per 10,000 inhabitants practising sports and enrolled in sport associations. Year Source: ISTAT, Statistiche culturali Anno 7, , published in 2004 on data of Comitato Olimpico Nazionale Italiano (CONI) Voters Percentage of people that effectively vote over the total numbers of voters in the 11 June 1995 Italian Referendum. Source: our elaboration on Ministero dell Interno Family Average households in each province divided by average households in Italy. Year Source: our elaboration on ISTAT, CENSUS Crime association Crime associations including Italian Mafia per 10,000 inhabitants. Year Source: our elaboration on Ministero Grazie e Giustizia Amenities and disamenities Robberies Robberies per 10,000 inhabitants. Year Source: our elaboration on Ministero di Grazia e Giustizia Mount Dummy variable: 1non-coastal province with mountain surface50%; 0otherwise (number of 08,364). Source: our elaboration on ISTAT, Sistemi di indicatori Territoriali Coast Dummy variable: 1at least one side of the province on the coast; 0otherwise (number of 05,100). Source: our elaboration Park Dummy variable: 1presence of at least one national park; 0otherwise (number of 06,324). Source: our elaboration on Airport Dummy variable: 1international airport mainly; 0otherwise (number of 09,282). Source: our elaboration on (July 2007) University Dummy variable: 1presence of university in the province; 0otherwise (number of 05,610). With around 133,178 enrolments in the academic year 2007/2008 the Università di Roma La Sapienza is the biggest public university in Italy, while the smallest public university is the Università degli Stranieri di Siena with 500 enrolments. Source: our elaboration on MIUR Long and Short Distance Migration in Italy 117

9 118 B. Biagi et al. the out-migration. Conversely, the higher the unemployment rate in the origin the higher the out-migration (push factor) (DaVanzo, 1978). Here, the unemployment rate is also a way of measuring inter-provincial differences in employment opportunities. As far as demographic variables are concerned, we include the destination origin difference in both the total population and the percentages of age-subgroups (2039, 4065, 65). Human capital is proxied by the educational level of the population and in particular the number of residents with a secondary school diploma per 10,000 inhabitants. We also control for social capital both at a macro and at a micro level. At the macro level, we follow the work by Putnam (1993, 1995) and Helliwell & Putnam (1995) whereby we measure the level of social and political participation. Here we use the destinationorigin difference in: the number of people participating in sports associations and people working voluntarily in charity organizations (both standardized per 10,000 inhabitants); and the difference in the percentage of people that actually voted in the Referendum of 11 June 1995 over the number of potential voters. We also control for negative social capital measured as the destinationorigin difference in the number of crimes per 10,000 inhabitants (recorded in the Italian Penal Code relating to Mafia involvement). In addition, following the argument of a variety of social capital researchers (Banfield, 1958; Coleman, 1988; Hao, 1994; Fukuyama, 1995, 1997; Guiso et al., 2004; Alesina & Giuliano, 2007), we include a variable for family capital, measured as the difference between the family size in the destination and origin, normalized for the average for Italy as a whole. Following the tradition of equilibrium studies on migration and hedonic studies (Graves, 1976; Roback, 1982; Blomquist et al., 1988), the amenity-related quality of life dimension is measured by means of six variables. The first variable, representing disamenities, is the destinationorigin difference in the number of robberies (per 10,000 inhabitants). Three environmental amenities variables are also included: a dummy for non-coastal provinces with at least mountain surface 50%, a dummy for the destination province being on the coastline and a dummy for destination provinces with a national park. Finally, in order to control for some additional aspects possibly related to the existence of urbanization economies, we employ a dummy variable to capture the presence of an international airport in the destination province. 4. Interregional Migration in Italy Interregional migration flows in Italy have gone through various different phases during the second half of the 20th century. In the early post-war years spanning from the early 1950s through to the early 1970s, there were intense migration flows from the south of Italy (mainly rural) to the more urbanized north. The migration system was clearly a disequilibrium system in that migrants from poorer low wage regions were moving in very large numbers to higher wage regions. That this is the case can be seen clearly in Figure 1 where the 103 Italian provinces are ordered*moving from left to right*from north to south. Figure 1 shows the net flows of migrants into each province in It becomes immediately apparent that almost all of the provinces north of Rome exhibited positive net inflows whereas almost all provinces south of Rome exhibited negative net migration flows. In particular, the largest net outflows were exhibited by Rome

10 Long and Short Distance Migration in Italy 119 Figure 1. Net migration flows by province Note: In the graph all types of residential movements (intra-province, interprovince, inter-region) are included. Provinces are ordered from north to south. Source: Our elaboration from ISTAT, Popolazione e Movimento Anagrafico dei Comuni [Population and Demographic Movements by Municipality] (1992). and Naples, while the largest net inflows were exhibited by the major northern cities such as Milan, Turin, Bologna and Florence. This pattern of southnorth migration greatly attenuated, however, from the mid-1970s onwards. Indeed, between the mid-1970s and the mid-1990s the south north migration flows slowed down considerably. Figure 2*constructed in a similar manner to Figure 1*depicts the net migration flows by province in While the northsouth distribution of net migration flows is still similar to that in the earlier era, the absolute levels of these net positive and negative flows are much lower than two decades earlier. Moreover, by this time, some of the major northern cities such as Milan, Genoa and Florence were themselves also experiencing net outflows of people of a similar magnitude to those exhibited by Rome and Naples. This pattern of migration between the mid-1970s and mid-1990s has been termed the empirical puzzle (Faini et al., 1997), in that while major differences still persisted between high unemployment rates in the south and low unemployment rates in the north, southnorth migration rates were surprisingly low, and in particular much lower than in the previous decades. The reasons for this slow down in migration between the mid-1970s and mid-1990s are still not entirely clear and various explanations have been put forward, including the role of public sector investment in southern regions (Attanasio & Padoa-Schioppa, 1991), increasing northsouth house price differentials (Cannari et al., 2000), the growth in the absolute living standards in the south (Faini & Venturini, 1994), inefficiencies in interregional job matching processes (Casavola & Sestito, 1993; Faini et al., 1997), and changes in industrial structures and systems (Murat & Paba, 2001). Whatever the reason or mix of reasons for the migration slowdown between the mid-1970s and the mid-1990s, between the mid-1990s and the 2000s Italian

11 120 B. Biagi et al. Figure 2. Net migration flows by province Note: In the graph all types of residential movements (intra-province, interprovince, inter-region) are included. Provinces are ordered from north to south. Source: Our elaboration from ISTAT, Popolazione e Movimento Anagrafico dei Comuni [Population and Demographic Movements by Municipality] (1992). Figure 3. Net migration flows by province Note: In the graph all types of residential movements (intra-province, interprovince, inter-region) are included. Provinces are ordered from north to south. Source: Our elaboration from ISTAT, Popolazione e Movimento Anagrafico dei Comuni [Population and Demographic Movements by Municipality] (1992).

12 Long and Short Distance Migration in Italy 121 Figure 4. Long distance net migration flows by province and region Note: Provinces are ordered from north to south. Source: Our elaboration from ISTAT, Popolazione e Movimento Anagrafico dei Comuni [Population and Demographic Movements by Municipality] (1992). southnorth migration flows started to recover. Figure 3*based on the 2002 migration data*shows that the general southnorth migration pattern from the period up to the mid-1970s has reappeared with a vengeance, except for one particular aspect. Net migration outflows from Milan are, along with those from Naples, the largest for any province in Italy. Small net outflows are also observed from other large northern cities such as Genoa and Turin, while many smaller northern cities benefit from large net inflows. Once again, a variety of explanations for this migration turnaround have been offered, including reductions in public sector transfers to the south (Basile & Causi, 2005), the success of northern industrial districts (Basile & Causi, 2005), and the resulting strong northern demand for in-migrant low skilled (Bonifazi, 2001) and high skilled (Piras, 2005a, 2005b) workers. At the same time as internal Italian explanations are sought, it may be the case that this migration turnaround is also related to external issues. In particular, the increasing disequilibrium interregional labour flows evident since the mid- 1990s reflect an emerging EU-wide pattern of interregional divergence (Barca, 2009), driven by increased spatial competition between regions in response to the new era of global competition. These emerging EU-wide interregional divergence patterns are generally regarded as being related to the complex interactions between agglomeration effects, and the migration behaviour of high human capital people (Faggian & McCann, 2009b), and EU regions characterized by high levels of agglomeration and international connectivity appear to be the major beneficiaries of these market integration and globalization processes.

13 122 B. Biagi et al. Figure 5. Short distance net migration flows by province and region Note: Provinces are ordered from north to south. Source: Our elaboration from ISTAT, Popolazione e Movimento Anagrafico dei Comuni [Population and Demographic Movements by Municipality] (1992). A problem with all of these explanations, however, is that while they provide some possible explanations for the increasing long distance southnorth labour drift since the mid-1990s, they provide no explanation as to why smaller cities in the north are systematically growing. Possible clues as to what might be happening can be gleaned from the fact that while the smaller northern cities are growing there are also large net outflows from Milan as well as small outflows from Turin and Genoa. It may well be the case therefore that another migration process over shorter distances is operating simultaneously with the long distance southnorth labour flows. It is therefore instructive to try to split these two types of migration in order to identify their major characteristics. In order to analyse long distance migration movements, we group the Italian provinces into three macro-regions, namely the north, the centre and the south. We define long distance migration as migration between provinces belonging to non-adjacent macro-regions, i.e. migration from the south to the north or from the north to the south. Adopting this approach, as we see in Figure 4, net outflows of long distance migrants are almost entirely a phenomenon of provinces in the south. Contrary to long distance movements, short distance movements (i.e., between provinces within the same region) are rather similar for all three northern, central and southern macro-regions (see Figure 5). Many large cities appear to suffer net outflows to adjacent provinces whereas smaller cities tend to exhibit net inflows from adjacent provinces. As such, there appears to be an emerging pattern of short distance migration out from some of the large urban areas into some of the smaller urban areas, particularly within the northern region of Italy.

14 Long and Short Distance Migration in Italy 123 Why this should be the case is as yet not clear. The descriptive analysis of Bonifazi & Heins (2000) detects differences in the features of short distance and long distance inter-provincial migration in Italy for the time span However, as yet, there is no real empirical evidence regarding the different features driving the short distance versus long distance migration flows. This paper explicitly aims to model these different types of migration flows in order to identify the role played by economic, social and environmental factors in determining these complex mobility patterns. This research therefore represents the first time that the key features of short distance versus long distance migration have been so explicitly modelled in the case of Italy. 5. Results We begin the analysis of the econometric results in Table 3 by considering all migration moves together as if they were a single migration phenomenon. As expected, the level of migration flows is negatively related to the distance between the provinces. However, many of the other results are rather difficult to interpret in the light of migration theory as they are not consistent with any of the disequilibrium, equilibrium or escalator theories of migration. This would suggest that a migration model with all flows included is probably mis-specified in that it is likely to be mixing up quite different migration phenomena. Following the discussion in Section 2, it would appear to be more useful to consider long distance and short distance migration flows separately. Indeed, when we split up the two different types of migration flows, the results start to make much more sense. If we consider just the long distance flows (Table 4) we see that migration appears to follow the logic of the disequilibrium model, where economic/labour market variables play a dominant role. Our results show that people tend to migrate to provinces with higher GDP per capita (highly correlated with higher wages) and lower unemployment rates. The presence of the 2039 age group is also important in attracting long distance migrants and this is consistent with the finding that in many countries this is the age group which is most migratory in response to wage signals and who are best placed to take account of the gains from migration associated with human capital. Recent estimates suggest that high human capital migrants of this age group contribute as much as 80% of the value-added in the economy (McDonald & Temple, 2006). Provinces with a local university and with a better educated population (human capital) are also favoured, while, ceteris paribus, locations with more affordable houses are preferred. In terms of social and amenity factors, long distance migration is negatively related to crime levels but surprisingly unrelated (or even negatively related in the case of natural parks) to natural amenities, showing that in long distance movements economic variables play an important role together with urban agglomeration economies (proxied by the presence of airports and/or universities). The results are different for short distance migration 5 (Table 5) which is primarily directed towards relatively smaller provinces with better quality of life. Moreover, natural amenities such as being close to the coast, now play a role. There is no age effect or human capital effect. Interestingly*and contrary to long distance movements*economic variables do not play a dominant role.

15 124 B. Biagi et al. Table 3. Model 1: all migration flows (observations: 10,506) NEGBIN GMM2S Spatial variable Coefficient z-value Coefficient z-value Distance (km) *** *** 9.54 Economic variables DGDP *** D Unemployment *** Demographic variables D Population 3.96e07*** * 1.88 D Age *** * 1.87 D Age * 1.85 D Age *** Human capital D Diploma Social capital D Sport ** D Voters ** D Family ** 1.98 D Crime association * Amenities and disamenities D Robberies *** Mount *** ** 2.12 Coast * 1.67 Park *** ** 2.19 Airport *** *** Universities *** *** 4.13 Alpha GLM statistics (alpha constant) (1/d) Deviance (1/d) Pearson AIC BIC 84, Note: P-values are in parentheses: *, ** and *** indicate significance at the 10%, 5% and 1% level, respectively. The models are performed with robust standard errors. Heterogeneity parameter a is calculated by the NB estimator. Following Hilbe (2007) Deviance, Pearson and AIC and BIC are calculated performing a GLM in which the heterogeneity parameter a of the negative binomial is held as constant. The diagnostic test for instrumental variables/gmm is taken from Baum et al. (2007). Diagnostic tests GMM2S: Model 1: all migration flows Endogeneity test (DGDP, D P Unemployment) H 0: Exogeneity No reject H 0 KleibergenPaap rk LM statistic P (underidentification test) H 0: Underidentification Reject H 0 AndersonRubin Wald test 4.77 P (weak instruments) StockWright LM S statistic 4.76 P (weak instruments) H 0: B10 and overidentifying No reject H 0 restrictions are valid

16 Long and Short Distance Migration in Italy 125 Table 4. Model 2: long distance movements (observations:1,656) NEGBIN GMM2S Spatial variable Coefficient z-value Coefficient z-value Distance (km) *** *** 2.53 Economic variables DGDP *** *** 3.04 D Unemployment *** *** 2.11 Demographic variables D Population *** *** 2.54 D Age *** *** 3.39 D Age * *** 3.38 D Age *** Human capital D Diploma *** ** 2.19 Social capital D Sport *** *** 2.84 D Voters *** 2.96 D Family *** 4.17 D Crime association *** Amenities and disamenities D Robberies *** 4.5 Mount *** 3.12 Coast *** *** 3.35 Park * Airport *** *** 7 Universities *** *** 4.66 Alpha GLM statistics (alpha constant) (1/d) Deviance (1/d) Person AIC BIC 10, Note: P-values are in parentheses: *, ** and *** indicate significance at the 10%, 5% and 1% level, respectively. The models are performed with robust standard errors. Heterogeneity parameter a is calculated by the NB estimator. Following Hilbe (2007) Deviance, Pearson and AIC and BIC are calculated performing a GLM in which the heterogeneity parameter a of the negative binomial is held as constant. The diagnostic test for instrumental variables/gmm is taken from Baum et al. (2007). Diagnostic tests GMM2S: Model 2: long distance flows Endogeneity test (DGDP, D P Unemployment) H 0: Exogeneity No reject H 0 KleibergenPaap rk LM statistic P (underidentification test) H 0: Underidentification Reject H 0 AndersonRubin Wald test P (weak instruments) StockWright LM S statistic P (weak instruments) H 0: B10 and overidentifying Reject H 0 restrictions are valid

17 126 B. Biagi et al. Table 5. Model 3: short distance movements (observations: 1,656) NEGBIN GMM2S Spatial variable Coefficient z-value Coefficient z-value Distance (km) *** *** 5.54 Economic variables DGDP E D Unemployment *** Demographic variables D Population *** 9.87E D Age D Age D Age Human capital DDiploma Social capital D Sport E D Voters D Family D Crime association Amenities and disamenities D Robberies Mount Coast *** ** 2.29 Park Airport *** *** 5.13 Universities *** *** 3.17 Alpha GLM statistics (alpha constant) (1/d) Deviance (1/d) Person AIC BIC 1, Note: P-values are in parentheses: *, ** and *** indicate significance at the 10%, 5% and 1% level, respectively. The models are performed with robust standard errors. Heterogeneity parameter a is calculated by the NB estimator. Following Hilbe (2007) Deviance, Pearson and AIC and BIC are calculated performing a GLM in which the heterogeneity parameter a of the negative binomial is held as constant. The diagnostic test for instrumental variables/gmm is taken from Baum et al. (2007). Diagnostic tests GMM2S: Model 3: short distance flows Endogeneity test (DGDP, D P Unemployment) H 0: Exogeneity No reject H 0 KleibergenPaap rk LM statistic P (underidentification test) H 0: Underidentification Reject H 0 AndersonRubin Wald test 3.13 P (weak instruments) StockWright LM S statistic 3.10 P (weak instruments) H 0: B10 and overidentifying No reject H 0 restrictions are valid

18 Long and Short Distance Migration in Italy 127 Taken together these results suggest that long distance migration in Italy is mainly driven by economic determinants whereas in short distance migration people give more weight to quality of life and amenities differences. Many models of migration, however, encounter endogeneity problems, in that the left hand side and right hand side variables are often partially co-determined, because increasing migration may increase destination nominal land prices and wages, and therefore GDP (Greenwood, 1997). In a count models framework, the issue of endogeneity can be dealt with by using nonlinear instrumental-variable techniques and Generalized Method of Moments (GMM) suggested by Mullahy (1997); see also Winkelmann, 2008). Specifically, we use a two-stage GMM (GMM2S) robust estimator and the routines and tests presented in Baum et al. (2007). The economic variables included in the model (GDP and Unemployment rate) are all suspected of endogeneity and need to be instrumented for. To do so we use three different instruments. The first instrument is the performance of the football teams in the destination province. The underlying hypothesis is that while the performance of a football team is related to the previous investments made by the team and, a fortiori, to the economic wealth of the province, 6 the performance of the football team itself does not influence the decision of people to migrate in a particular province. In order to build the instrumental variables to proxy the wealth of a province, we collect the ranking of the four professional football leagues in Italy, namely, Serie A (Premier League), Serie B, C1, C2, and one nonprofessional league Dilettanti. In total, we count 92 positions in the rank (the first 18 are in Serie A, from 19 to 38 are in Serie B and so on). We give 92 points to the first team in Serie A, 91 to the second, 90 to the third and so on; we then sum all the points for the teams belonging to the same province. 7 This calculation is done for the championships in the years 1994, 1995, 1996, 1997, 1998, 1999 and the final variable (Football) is the average performance of each province in the time span The second instrument is the industry mix employment rate à la Bartik (1991) and Blanchard & Katz (1992). The index for a province s in the period (t, tn) is defined as: INDMIX s X S t is +EMP GR t;tn i ;ITA (8) where asis t is the province employment share in industry i (one-digit SIC) in the initial year t (in this case 1991) and EMP GR t;tn i ;ITA is the growth rate in industry i for the whole of Italy in the period t, tn (in this case ). In practice the index measures the hypothetical employment rate growth if the province grew at the national level over the time span under analysis. Changes in national industry are the exogenous shifters (Faggian et al., 2010). The third instrument is represented by the number of ATM machines per 10,000 inhabitants in 1996, which is exogenous with respect to migration flows in 2001, but highly correlated to the level of per-capita GDP. The instrumental variables estimation is performed using the Stata command ivreg2 and GMM2S robust to account for heteroskedasticity (Baum et al., 2007). The endogeneity test (see bottom of Tables 35), fails to reject the null hypothesis that the economic regressors may be treated as exogenous. In other words, endogeneity does not seem to be a major problem in our estimations. However, we still report both results without and with correction for endogeneity. Both results are

19 128 B. Biagi et al. consistent with the idea that long distance migration responds to increases in income and unemployment while short distance movements are more responsive to amenities. 6. Conclusions Although many papers have debated the disequilibrium vs. equilibrium migration models, not many contributions have highlighted that these two models might, in fact, be two sides of the same coin and are not totally irreconcilable. Different migration movements may respond differently to economic incentives. In the case of Italy, for instance, long distance movements from the poorer more rural south to the more industrialized richer north might be predominantly the result of differences in economic opportunities, while the more recent short movements from large cities (mostly located in the north) to their hinterland or to smaller neighbouring provinces might be partially motivated by the search for a better quality of life. This paper provides some initial evidence that long distance migration between Italian provinces better conforms to the expectations of a disequilibrium model of migration, while in contrast, short distance movements between adjacent cities show some features of the equilibrium model of migration. The results are robust after controlling for possible endogeneity problems. As such, any migration model which attempts to account for Italian interregional mobility patterns in general will be mis-specified because the underlying processes of these two simultaneously-operating migration systems are very different. Moreover, our results also differ markedly from those of Cheshire & Magrini (2006) in that our observations suggest that natural amenity-driven migration in Italy only operates within the same region, not at the level of the country as a whole. As far as we are aware, this is the first time that the different types of simultaneously-operating short distance and long distance interregional migration flows have been decomposed and analysed for a country in this particular way, and it will be instructive to identify whether the patterns uncovered in Italy are also reflected in other countries. Notes 1. From an administrative point of view, Italy is divided into regions, provinces and municipalities. The number* and the boundaries*of the provinces and municipalities have changed over time. As the majority of studies at a province level, this work analyses internal migration in 103 provinces according to the 1992 classification. The Italian provinces correspond to the EU classification of NUTS See Kennedy (2008) for a more thorough description of these models. 3. The score test is 2.42 with a t-probability Pjtj0.000, hence the null hypothesis of no overdispersion is rejected (Hilbe, 2007). 4. Data on inter-provincial movements divided according to the directions of movement (i.e. flows between provinces belonging to the same region or flows between provinces belonging to different regions) have been issued by ISTAT since 1993 in the publication named Movimento Migratorio della Popolazione Residente. In the paper, data referring to 1972 and 1992 in Figures 1 and 2 come from another ISTAT publication Popolazione e Movimento Anagrafico dei Comuni. In this publication, movements are collected at a municipality level and include all types of residential inflows and outflows (people coming from or moving to: a municipality of the same province, of a different province). To avoid problems related to data heterogeneity, Figure 3 therefore also uses the same source. Meanwhile, Figures 4 and 5 use the data from Movimento Migratorio della Popolazione Residente. 5. Short distance province to province movements may also include commuting patterns. In order to exclude those, we consider just short distance movements greater than 70 km. This threshold distance allows us to exclude most commuting patterns. Taking for instance the case of the largest city in Italy, Milan, many people