policy adoption rules and global warming although there is widespread agreement about the dangers of global warming and the resulting need to cut down emissions there does not seem to be general agreement about the exact form the policy should take or the timing of its adoption failure to adopt and implement policies against global warming reflects the complexity of the problem the uncertainties of climate change and the cost of policy adoption issues associated with the interactions between uncertainties and irreversibilities in determining the timing of policy adoption are analyzed by using the methodology of optimal stopping rules optimal policy functions are derived for cooperative and noncooperative solutions with differential game representation issues associated with the empirical application of the optimal policy rules are also considered

shaky roads and trembling exports assessing the trade effects of domestic infrastructure using a natural experiment abstract our knowledge of the trade effects of domestic infrastructure is very limited the reason is twofold first data needed to examine these effects are not readily available second identifying such effects requires properly addressing potential endogeneity problems affecting the relationship between internal infrastructure and trade in this paper we overcome these limitations by combining firm level export data with detailed geo referenced information on chile and by exploiting the earthquake that took place in this country in 2010 as an exogenous source of variation in available infrastructure and thereby in transport costs we find that diminished transportation infrastructure had a significant negative impact on firms exports

the district effect and the competitiveness of manufacturing companies in local productive systems the present study evaluates the existence of differences in competitiveness of spanish industrial firms as a consequence of the district effect a quantitative analysis has been performed in order to assess external competitiveness taking into account whether firms are located in industrial districts in the sense proposed by marshall becattini or remain isolated the methodological approach considers geographical and sectoral variables it attempts to establish the existence of a relationship between sectoral specialisation and business efficiency measured as the capacity to export in local productive systems most of the variables come from a 1991 fiscal data set and the territorial units of analysis are 332 municipalities with a population of over 15 000 inhabitants from the results on the econometric model it can be inferred that the geographical concentration of companies in the same activity positively influences their level of competitiveness

endogenous future preferences and conservation a dynamic optimization model is developed in whichuncertainty about future preferences is endogenous namely depending on the state of the environment atthe time the change in preferences occurs endogeneizing preferences not only provides economicintuition to previous results but also implies thatoptimal policies are less conservative

economics and sustainability balancing trade offs and imperatives the concept of sustainability has been increasingly invoked in scholarly and public policy debates discussion has been hampered however by uncertainty and lack of uniformity in the meaning of sustainability this paper seeks to identify some common ground among economists ecologists and environmen tal ethicists two issues seem salient require ments for intergenerational and the defi nition of social capital to be provided to future generations a concept of safe minimum standard which has received at least some recognition in the ecology philosophy and eco nomics literatures may provide the beginnings of a common ground for debate about sus tainability jel q2

europe s tired poor huddled masses self selection and economic outcomes in the age of mass migration during the age of mass migration 1850 1913 one of the largest migration episodes in history the united states maintained a nearly open border allowing the study of migrant decisions unhindered by entry restrictions we estimate the return to migration while accounting for migrant selection by comparing norway to us migrants with their brothers who stayed in norway in the late nineteenth century we also compare fathers of migrants and nonmigrants by wealth and occupation we find that the return to migration was relatively low 70 percent and that migrants from urban areas were negatively selected from the sending population keep ancient lands your storied pomp cries she with silent lips give me your tired your poor your huddled masses yearning to breathe free the wretched refuse of your teeming shore send these the homeless tempest tost to me i lift my lamp beside the golden door emma lazarus 1883

the determinants of earnings a behavioral approach we survey the determinants of earnings and propose a framework for understanding labor market success we suggest that the advantages of the children of successful parents go considerably beyond the benefits of superior education the inheritance of wealth or the genetic inheritance of cognitive ability we suggest that noncognitive personality variables such as attitudes towards risk ability to adapt to new economic conditions hard work and the rate of time preference affect both earning and the transmission of economic status across generations

engaging students in quantitative analysis with short case examples from the academic and popular press following the completion of microand macroeconomics principles courses for which the majority of students are enrolled to fulfill requirements for other majors economics majors take two intermediate micro and macro courses a course in statistics econometrics and some field courses that may or may not include more quantitative methods john siegfried et al 1991 in a national survey michael watts and i found some differences between the way statistics and econometrics courses are taught and the way the other undergraduate economics courses are taught becker and watts 1996 in particular problem sets are used more in statistics and econometrics than in other undergraduate economics courses curiously however those applications are not based on events reported in newspapers magazines and journals that economists read how timely and relevant can problem sets be if they are not documented in current events ideally instructors set problems raised by their own research and consulting problems students can expect to see on their jobs after all the rationale for teaching statistics and econometrics outside a mathematics department rests on a belief that there is something special about economic analyses that is economists use of statistics is tied to the issues they face although the calculation of a mean and a median for example is the same in medicine and economics a discussion of the average duration of economic expansions since world war ii is more pertinent to those majoring in economics than is a discussion of average blood pressure or average time to dementia with mad cow disease the importance of economic tleory is often lost when mathematicians attempt to make situations real as seen for example in the chance course j laurie snell and john finn 1992 where a potpourri of statistical applications are presented with no disciplinegrounded analyses to teach students to apply the tools of statistics to actual situations and data encountered by economists there is little justification for examples involving the drawing of balls from urns flickng of spinners tossing of coins or contrived card and dice tricks yet these methods of generating data continue to be found in the activity based teaching and assessment discussants william greene new york university robin lumsdaine brown university kim sosin university of nebraska omaha

wage and labor supply effects of illness in cote d ivoire and ghana instrumental variable estimates for days disabled abstract sickness should make individuals less productive but there are problems in measuring this effect first how is adult morbidity measured in a household survey second how is the impact or morbidity on productivity inferred if earning is partly used to improve health self reported functional activity limitation due to illness is considered an indicator of morbidity for wage earners and self employed people to deal with both the measurement and joint determination problems an instrumental variable estimation approach is used where local food prices and health services instrument for disability days that reduce wages by at least 10 and hours by 3 or more

the cultural revolution and returns to schooling in china estimates based on twins abstract this paper investigates the returns to schooling in china for the cultural revolution cr cohort and the non cr cohort using a new set of chinese twins data applying the fixed effects model on twins data which helps to control for the genetic and family background effects this paper examines whether the cr cohort has smaller economic returns to schooling than the non cr cohort the empirical results in this paper indicate that the cultural revolution has not played a significantly adverse role in the returns to schooling

a human capital model of the effects of ability and family background on optimal schooling levels this paper develops a theoretical model of optimal schooling levels where ability and family background are the central explanatory variables we derive schooling demand and supply functions based on individual wealth maximization using nlsy79 data we stratify our sample into one year fte work experience cohorts for 1985 1989 mincer s 1974 overtaking cohort the years of work experience at which individuals observed earnings approximately equal what they would have been based on schooling and ability alone corresponds to 13 fte years of work experience yielding on average a rate of return of 9 6 percent and an average optimal 11 4 years of schooling

iq and stock market participation stock market participation is monotonically related to iq controlling for wealth income age and other demographic and occupational information the high correlation between iq and participation exists even among the affluent supplemental data from siblings studied with an instrumental variables approach and regressions that control for family effects demonstrate that iq s influence on participation extends to females and does not arise from omitted familial and nonfamilial variables high iq investors are more likely to hold mutual funds and larger numbers of stocks experience lower risk and earn higher sharpe ratios we discuss implications for policy and finance research

the firms that feed industrial districts a return to the italian source italian industrial districts comprise a great variety of firms and are criss crossed by various networks and business groups although the vast majority of industrial district firms are relatively small it is a mistake to assume that they are organizationally symmetrical and that they mimic the supposedly dominant norms of the communities in which they are located larger firms frequently organize production among groups of smaller firms introduce technological innovations and expand existing markets copyright 1999 by oxford university press

estimates of the economic returns to schooling from a new sample of twins this paper uses a new survey to contrast the wages of genetically identical twins with different schooling levels multiple measurements of schooling levels were also collected to assess the effect of reporting error on the estimated economic returns to schooling the data indicate that omitted ability variables do not bias the estimated return to schooling upward but that measurement error does bias it downward adjustment for measurement error indicates that an additional year of schooling increases wages by 12 to 16 percent a higher estimate of the economic returns to schooling than has been previously found copyright 1994 by american economic association

parental wealth and adult children s welfare in marriage abstract many studies find that parental resources importantly determine children s human capital schooling returns and earnings the collective household approach suggests that in addition parental resources of marital partners may importantly affect resource distributions within marriage this paper presents empirical results consistent with this framework they suggest that parental wealth continues to play roles in augmenting welfare of children into adulthood beyond provision of human capital in early life cycle stages or direct financial aid during adulthood and that actual transfers from parents to adult children do not fully measure influences of parental wealth on behaviors and welfare of adult children

using unemployment rates as instruments to estimate returns to schooling i use state unemployment rates during a person s teenage years to estimate the returns to schooling a higher unemployment rate reduces the opportunity costs of attending school using the same 1980 census data set that angrist and krueger 1991 use i also estimate returns to schooling with a modified version of their quarter of birth instrument the estimates from the two stage least squares 2sls model using the unemployment rate and the model using the quarter of birth instruments are almost identical in addition these 2sls estimates are larger than the ordinary least squares ols estimates supporting this counterintuitive yet prevalent result in the literature

interindustry r d spillovers rates of return and production in high tech industries this paper presents estimates of the productivity and factor bias effects of interindustry r d spillovers for five high tech industries each industry is distinguished as a separate spillover source the industries are each affected by r d spillovers and are themselves spillover sources thus a spillover network between the industries is estimated private and social rates of return to r d capital are calculated the private rates of return are generally greater than the returns to physical capital in addition the social rates of return are greater than the private rates the results show that there are significant differences between industries as to their importance as sources of r d spillovers this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item

innovation performance and embeddedness in networks evidence from the ethiopian footwear cluster this study focuses on innovation in a cluster of informal shoemaking firms in ethiopia namely the mercato footwear cluster it examines how differently those firms are embedded in networks and how heterogeneous they are in absorptive capacity and how this heterogeneity affects their innovation performance business interactions with buyers suppliers and other producers are the major channels through which knowledge flows into the cluster these business networks are mainly built on trust and long term relationships and tend to be selective the study reveals that despite homogeneity in social background the firms in the cluster behave and perform differently based on econometric analysis we document a positive and strong effect of local network position and absorptive capacity on innovation performance

intergenerational transmission of poverty and inequality parental resources and schooling attainment and children s human capital in ethiopia india peru and vietnam abstractacademic and policy literatures on intergenerational transmissions of poverty and inequality suggest that improving schooling attainment and income for parents in poor households will lessen poverty and inequality in their children s generation through increased human capital accumulated by their children however magnitudes of such effects are unknown we use data on children born in the twenty first century in four developing countries to simulate how changes in parents schooling attainment and consumption would affect poverty and inequality in both the parents and their children s generations we find that increasing minimum schooling or income substantially reduces poverty and inequality in the parents generation but does not carry over to reducing poverty and inequality substantially in the children s generation therefore while reductions in poverty and inequality in the parents generation are desirable in themselves to improve welfare among current adults they are not likely to have

how does trust affect performance in the supply chain the moderating role of interdependence abstract this paper focuses on the positive relationship between trust and performance in the supply chain and investigates whether and how the interdependence structure of the supply chain moderates this relationship interdependence occurs in supply chains because supply chain partners depend upon one another for product and process accomplishments and for the tangible and intangible resources owned by their partners framing the supply chain as a complex adaptive system we argue that in supply chain contexts both the degree of interdependence i e the average number of interactions among the supply chain firms and the overall interdependence pattern which maps with who each supply chain firm interacts moderate the relationship between trust and supply chain performance the proposed conceptual framework is operationalized through the nk fitness landscape model and tested using simulation and tobit regression analyses results confirm that the specific interdependence pattern that characterizes the supply chain has a significant moderating effect on the relationship between trust and supply chain performance while the moderating effect exerted by the degree of interdependence is not statistically significant

industrial districts district effect and firm size the italian evidence the paper analyses the transformations that occurred in the italian industrial districts ids by empirically estimating the role of the district effect on firm performance over recent decades given their ability to manage upper level and size related business practices medium sized firms emerge as local players best able to exploit their embeddedness in the districtual system and leverage districtual assets however these effects are only present in firms belonging to the industrial specialization of the district an additional result of the empirical analysis shows that the leading role of medium sized firms is critical in younger districts where medium sized firms lead the renewal of the id and its adaptation to the changes of the competitive environment as most italian ids are specialized in traditional sectors this evidence contributes to understanding the mechanisms connecting the competitiveness of the traditional industry and its localised organizational structure the paper also provides a discussion of the future of ids including the relevance of the evolutionary stage of the district on the performance of affiliated firms and their reproducibility over time

home bias and international risk sharing twin puzzles separated at birth abstract we document that international home bias in debt and equity holdings declined during the period 1993 2003 at the same time as international risk sharing increased using panel data regressions for oecd countries we demonstrate that less home bias is associated with more international risk sharing more generally we show that more financial integration is associated with more risk sharing when we measure financial integration as the ratio of foreign assets to gross domestic product our results indicate that risk sharing and international financial integration are closely related empirical phenomena

estimating the return to endogenous schooling decisions via conditional second moments this paper employs conditional second moments to identify the impact of education in wage regressions where education is treated as endogenous this approach avoids the use of instrumental variables in a setting where instruments are frequently not available we employ this methodology to estimate the returns to schooling for a sample of australian workers we find that accounting for the endogeneity of education in this manner increases the estimated return to education from 6 percent to 10 percent

risk sharing from international factor income explaining cross country differences access to world capital markets and net investment income flows between countries help protect national income from country specific output shocks i empirically study what factors explain cross country differences in the extent of risk sharing from international factor income an index of investor protection is the leading causal variable for the estimated amount of risk sharing over the 1985 to 2004 period improving investor protection in russia to denmark s level implies five times larger risk sharing compared to the sample average these results indicate one possible way to reap large potential benefits from international risk sharing

role of industrial district externalities in export and value added performance evidence from the population of italian firms becchetti l de panizza a and oropallo f 2007 role of industrial district externalities in export and value added performance evidence from the population of italian firms regional studies 41 601 621 the paper tries to shed light on the export and value added performance of industrial districts by integrating information on the population of italian firms from the asia database of the italian statistical institute with balance sheet data for all limited liability companies in selected manufacturing industries the findings show that firms located in industrial districts specialized or not in the leading manufacturing activity of the district export more and have higher added value than firms located elsewhere net of the impact of relevant controls the robustness check undertaken on the agglomeration performance nexus detects as expected a significant relationship between dichotomous district indicators and global and industry specific continuous measures of agglomeration and specializat

the effect of income on subjective well being evidence from the 2008 economic stimulus tax rebates this paper uses tax rebate payments from the 2008 economic stimulus to estimate the effect of a one time change in income on three measures of subjective well being life satisfaction health satisfaction and affect the income effect is identified by exploiting the plausibly exogenous variation in the payment schedule of the rebates using both ordinary least squares and two stage least squares estimators i find that the rebates had a large and positive impact on affect which is explained by a reduction in feelings of stress and worry for life satisfaction and health satisfaction there is weaker evidence of a positive impact

nature of transfers income tax function and empirical estimation of elasticity of taxable income for brazil abstractthis article aims to estimate the elasticity of taxable income eti taking into account the nature of transfers and their use as a redistribution package involving cash and in kind transfers to households in brazil our contributions are twofold first we provide a simple model with balanced budget government that reveals the role played by cash and in kind transfers on the labour supply and income tax revenues thereof next in order to estimate eti in the presence of cash and in kind transfers brazilian population surveys pesquisa nacional por amostra de domicilios pnad are used to explore a limited tax reform that was implemented between 1997 and 1998 this reform only affected the higher income tax bracket our findings suggest that in kind cash transfers are positively negatively associated with reported taxable income and precise estimation of eti requires estimates of both types of transfers last we estimate the eti for brazil in the range from 0 4 to 1 3 not different fro

twin picks disentangling the determinants of risk taking in household portfolios this paper investigates risk taking in the liquid portfolios held by a large panel of swedish twins we document that the portfolio share invested in risky assets is an increasing and concave function of financial wealth leading to different risk sensitivities across investors human capital which we estimate directly from individual labor income also affects risk taking positively while internal habit and expenditure commitments tend to reduce it our microfindings lend strong support to decreasing relative risk aversion and habit formation preferences furthermore heterogeneous risk sensitivities across investors help reconcile individual preferences with representative agent models

place space and geographical exposure foreign subsidiary survival in conflict zones this study focuses on the role of geography in foreign subsidiary survival in host countries afflicted by political conflict we argue that survival is a function of exposure to conflicts and depends on the characteristics of place the conflict zone and space geographic concentration and dispersion of other home country firms the roles of place and space are explored using street level analysis of geographic information systems data for 670 japanese multinational enterprises mne subsidiaries in 25 conflict afflicted host countries over 1987 2006 through dynamic modeling of conflict zones as stretchable and shrinkable places relative to subsidiary locations we develop a means of characterizing a foreign subsidiary s exposure to multiple threats in its geographic domain our results show that greater exposure to geographically defined threats in both a static and a dynamic sense reduces the likelihood of mne survival the findings indicate moreover that both concentration and dispersion with other firms affect survival however the effects depend on where the firm is spatially located whether the firm is in a conflict zone and with whom home country peers or sister subsidiaries

monotone instrumental variables with an application to the returns to schooling for fifty years econometric analyses of treatment response have made extensive use of instrumental variable iv assumptions holding that mean response is constant across specified subpopulations of a population of interest 2 yet the credibility of mean independence conditions and other iv assumptions has often been a matter of considerable disagreement with much debate about whether some covariate is or is not a valid instrument in an application of interest there is therefore good reason to consider weaker but more credible assumptions to this end we introduce monotone instlumental variable miv assumptions holding that mean response varies weakly monotonically across specified subpopulations we study the identifying power of these miv assumptions and give an empirical application the findings reported here add to the literature developing nonparametric bounds on treatment effects 3 this paper uses the same formal setup as manski 1997 there is a probability space j x2 p of individuals each member j of population j has observable covariates xi e x and a response function yj t y mapping the mutually exclusive and exhaustive treatments t e t into outcomes yj t e y person j has a realized treatment zj e t and a realized outcome y 1 y zi both of which are observable the latent outcomes yj t

looking for a guide to protect the environment the development of the precautionary principle abstract if the precautionary principle is to become the guide of the international community for environmental protection policies an economic interpretation of the principle is in order the analysis of case studies and a survey of the recent decision theoretic literature show the lack of a fully satisfactory economic model more generally various theoretical and empirical results show that the principle cannot be assumed to apply a priori though it has been proposed by international treaties as a rule of thumb for situations of scientific uncertainty the precautionary principle could actually be inefficient

credit constraints in italian industrial districts italy is characterized by strong differences both in the productive and in the financial structure small and medium firms tend to concentrate in the so called marshallian industrial district whose productive system has been thoroughly studied but whose financial features are partially overlooked this paper aims at investigating how the location of a firm in an industrial district affects its ability to resort to external finance mostly bank loans the econometric analysis on a panel of 1700 firms over the 1989 1995 period shows that firms located inside industrial districts have an advantage in terms of financial relations with the banking system both the cost of credit and the probability to face financial constraints are lower nevertheless the cyclical pattern of this advantage is not in favour of district firms following the tightening of monetary policy increases in interest rates on bank loans are proportionally higher for firms inside the district furthermore also the advantage consisti

channels of interstate risk sharing united states 1963 1990 we develop a framework for quantifying the amount of risk sharing among states in the united states and construct data that allow us to decompose the cross sectional variance in gross state product into several components which we refer to as levels of smoothing we find that 39 percent of shocks to gross state product are smoothed by capital markets 13 percent are smoothed by the federal government and 23 percent are smoothed by credit markets the remaining 25 percent are not smoothed we also decompose the federal government smoothing into subcategories taxes transfers and grants to states

environmental issues and economic decisions in developing countries abstract this paper explains the key role of environmental economics in incorporating environmental concerns into decision making and in facilitating the more efficient management of natural resources as a step toward sustainable development it reviews concepts and techniques for valuation of environmental impacts for use in conventional cost benefits analysis as well as key related aspects including environmental impacts of economywide policies multicriteria analysis risk and uncertainty and discount rate issues several developing country case studies are summarized which cover a range of practical valuation methods the evidence presented suggests that the valuation techniques for determining use values may be applied successfully in appropriate cases but examples involving nonuse values are rare the use of multiobjective desicion methods also needs to be explored where economic valuation is not feasible

exploring the locus of invention the dynamics of network communities and firms invention productivity departing from prior research analyzing the implications of social structure for actors outcomes by applying either an ego network or a global network perspective this study examines the implications of network communities for the invention productivity of firms network communities represent dense and nonoverlapping structural groups of actors in a social system a network community lens helps identify new ways to study firms access to diverse knowledge inputs in a dynamic system of interorganizational relationships specifically we examine how the membership dynamics of a network community affect the invention productivity of member firms by either enabling or constraining access to broad diverse knowledge inputs our findings suggest first that a firm reaps the greatest invention benefits in a network community with moderate levels of membership turnover second a firm attains the greatest invention productivity when its own rate of movement across different network communities is moderate third we find that community members located in the core of their network community can benefit more from membership dynamics and prior community affiliations than those on its periphery in empirical analyses we use the evolving community structure of the network of interorganizational partnerships in the global computer industry over 1981 2001 to predict firms patenting rates

education human capital and growth a personal perspective this article reviews the literature on the relationship of economic growth to the education levels of the labor force the emphasis is on yoram ben porath s contribution to some of the issues in this field the endogeneity of schooling the role of the public sector as an absorber of educated labor and the importance of personal human capital created by investments in reputation and personal relationships the f connection

on sustainability and the economics of survival this paper investigates the implications of sustainability and survival strategies for economic analysis it reviews connections between the approaches used by economists and biological scientists in the study of survival the paper emphasizes the role of irreversibility and uncertainty in the investigation of sustainability issues implications of the results for the analysis of economic behavior are discussed

quasi option value and climate policy choices in the climate change issue the environmental irreversibility risk of an acceleration of mitigation policies if the worst happens has to be balanced with the investment irreversibility risk of over cautious policies to explore this balance we define an option value for a precautionary climate policy using the simplest decision making model we expose how option value relates to the expected value of future information using quantitative data from an integrated assessment model we find that most of the time the environmental irreversibility dominates the investment irreversibility for all cases explored here the order of magnitude of the option value was significant about 50 of the opportunity cost

valuing environmental functions tropical wetlands recent studies have suggested that tropical wetland systems may have a crucial economic role to play in development the following paper provides an overview of these benefits using the general framework of cost benefit analysis as the methodological approach to assessing wetland values an analysis of trade offs between conserving or converting tropical wetlands demonstrates that taking into account the opportunity cost of wetland loss leads to a lower level of conversion than would otherwise be the case finally the paper discusses the extensions and limitations of the production function approach as applied to valuing nonmarketed wetland benefits

does compulsory school attendance affect schooling and earnings we establish that season of birth is related to educational attainment because of school start age policy and compulsory school attendance laws individuals born in the beginning of the year start school at an older age and can therefore drop out after completing less schooling than individuals born near the end of the year roughly 25 percent of potential dropouts remain in school because of compulsory schooling laws we estimate the impact of compulsory schooling on earnings by using quarter of birth as an instrument for education the instrumental variables estimate of the return to education is close to the ordinary least squares estimate suggesting that there is little bias in conventional estimates every developed country in the world has a compulsory schooling requirement yet little is known about the effect these laws have on educational attainment and earnings 1 this paper exploits an unusual natural experiment to estimate the impact of compulsory schooling laws in the united states the experiment stems from the fact that children born in different months of the year start school at different ages while compulsory schooling laws generally require students to remain in school until their sixteenth or seventeenth birthday in effect the interaction of school entry requirements and compulsory schooling laws compel students born

environmental preservation and majority decisions in this paper we bring together the quasi option value literature with a majority rule community decision making scheme it is shown that the quasi option value is positive for a majority of voters if there exists a median voter who is dictatorial however the quasi option value can be negative for a majority or all community members given the standard assumptions of the literature for which the quasi option value for a single decision maker would always be positive but in some cases this leads to majority decisions in favor of the irreversible development of natural resources when future information is taken into account

thy neighbor s keeper the design of a credit cooperative with theory and a test economists now appreciate that resource allocation in less economically developed economies is profoundly influenced by non firm economic institutions however our theories of non firm institutions often suggest different answers to many questions including those of policy this paper illustrates a method for discriminating between alternative theories using data from german credit cooperatives from the nineteenth and early twentieth century germany we build a model of credit cooperatives designed to provide monitoring incentives and test this using nineteenth century data authors

the economics of sequential choice applied to quasi option value abstract this paper develops a general model that can be used to determine the value of sequential forecasts the model is used 1 to examine the interacting effects of strategies for coping with environmental uncertainty and 2 to explore the relationship between the theories of sequential choice and quasi option value the framework presented bridges these two schools of thought and provides a tool for evaluating one time e g climate change or repetitive e g pollution forecasts of environmental damage

species preservation and biodiversity value a real options approach abstract we evaluate biodiversity in a real options framework when the resources in use are substitutable we examine optimal conservation decisions given that a biodiversity loss is irreversible and that future use values are uncertain while species substitutability has been shown to reduce the value of diversity we show that the flexibility associated with substitutability is a source of value marginal species value is decreasing in the number of species but rising and convex in the value of the marginal species as we show in the two species homogenous model increased volatility raises biodiversity value and a positive correlation between species values both reduces the value of the pool of species and the value of biodiversity the role played by the correlation between the value of a species and the value of other species is reminiscent of the beta of a financial asset just like an asset with a negative beta derives additional value by providing insurance against fluctuations in the market portfolio a species whose value tends to move in the opposite direction as the species in use derives additional value from its higher probability to be available for substitution if the value of the species in use diminishes

gatekeepers in regional networks of innovators the internal density of a local network is said to increase the regionspecific knowledge stock and might lead to a comparative advantage however it might also lead to a lock in situation if local trajectories are directed towards inferior solutions accordingly it is argued that successful clusters are characterised by the existence of gatekeepers i e actors that generate novelty by drawing on local and external knowledge we attempt to answer questions related to the role and characteristics of gatekeepers within regional innovation systems by applying social network analysis based on patent data for four east german regions the regional networks appear to be significantly dierent with respect to the overall degree of interaction and with respect to their relative outward orientation concerning the characteristics of gatekeepers we find that size does not play the major role for being a gatekeeper it is rather absorptive capacity that matters for gatekeepers it also shows that public research organisations serve the functions of a gatekeeper to a higher degree than private actors

information and the dynamics of environmental protection the concept of the critical period earlier work on environmental decisions under uncertainty is extended from two periods to many permitting treatment of a richer variety of problems implications for pollution control policy of several different kinds of ecosystem recovery dynamics are considered in the context of improving information about ecosystem behavior and preferences for environmental goods multiperiod analogs of the two period concept of quasi option value are developed

thinking economically about climate change abstract uncertainty over both the regional impacts and timing of climatic changes the way they tend to magnify the likelihood of so called natural disasters and their irreversibility require careful analysis of policy options from an economic standpoint the best approach is to apply cost benefit thinking the essential trade off is between doing nothing now and investing in either important preventive or adaptive measures the choices involve analysis of incurring costs now against the benefits of reducing vulnerability and future damage costs for any given level of warming the aim is to minimize the sum of policy costs and costs of adaptation by individuals any resulting policy decision will have to address issues of international cooperation and compensation these considerations may in turn influence the resulting policy choices between carbon taxes marketable permits and regulatory restrictions

determinants of the internationalization of regions the role and effectiveness of public policy measures banno m piscitello l and varum c determinants of the internationalization of regions the role and effectiveness of public policy measures regional studies this paper assesses the role of public policy measures on outward internationalization of regions by including financial and non financial incentives among the determinants of the international competitiveness of regions it is found that the former are important to enhance their active internationalization but that variables related to the knowledge and competence base of regions are even more so financial incentives related to equity participation as well as non financial incentives related to the provision of information come out highly significant in stimulating outward internationalization the empirical analysis is conducted for the twenty italian nuts 2 regions over the period 2003 2008

innovation and industrial districts a first approach to the measurement and determinants of the i district effect boix r and galletto v innovation and industrial districts a first approach to the measurement and determinants of the i district effect regional studies the paper analyses an exhaustive database of patents granted in spain between 2001 and 2006 aggregated in a panel of 806 local labour markets classified by seven typologies of local production systems the analysis shows that marshallian industrial districts generate 30 of spanish patents and an innovative output per capita that is 47 above the national average and 31 larger than the manufacturing production systems of large firms the econometric estimates of a fixed effects model confirm the existence of an innovation district i district effect and its size the i district effect is mainly related to the presence of marshallian localization economies boix r et galletto v innovation et districts industriels une premiere approche de la mesure et des determinants des effets des districts d innovation regional studies nous analysons une base

labor market returns to two and four year college the paper examines labor market returns to a two and four year college education analysis of the 1972 national longitudinal survey of youth observation that the average person who attended a two year college earned about 10 percent more than those without any college education comparison with the wages of those who attended a four year college education

returns to foreign languages of native workers in the european union most of the literature on returns to languages is concerned with immigrants the authors study which uses the european community household panel survey for the period 1994 2001 infers returns to non native languages by native workers in nine countries of the european union the study differs from other studies that deal with the same issue in three respects first instead of using a dummy for each language they use the ratio of the population not proficient in a given country s national language and compare the results with the more traditional approach using dummies second they correct for time independent measurement errors in self reporting and find that the resulting iv estimates are much larger than those obtained by ols they also suggest that there is little room for time persistent errors and heterogeneity and that therefore their estimates should suffer ostensibly little from unobserved ability biases finally they estimate iv quantile regressions to illustrate how returns to languages vary at different points of the distribution of earnings

quasi option value some misconceptions dispelled abstract we discuss a couple of important issues in the recent literature on quasi option value we show that the assertion that quasi option value can be negative in a model with independent learning is based on confusion between quasi option value which is always positive and the net benefit of preservation of a natural environment subject to development which is not we also explore the significance of different assumptions about the nature of learning and show that the result that quasi option value is positive is surprisingly robust

the estimation of human capital by administrative archives in a static and longitudinal perspective the case of milan this paper focuses on the estimation of the latent variable human capital hc at disaggregated level worker by available routinely institutional data flows in particular we utilize the lombardy region administrative archive employment centers of the province of milan collecting information about careers of workers in the private sector of the milan area and administrative flows collecting mandatory workers individual income tax returns filed with the national internal revenue service first we propose and empirically estimate hc scores in a static referred to 2004 framework by means of a realistic measurement model within causal relationships among endogenous and exogenous investment hc indicators furthermore the model also specifies a set of concomitant indicators that not belonging to hc investment indicators have causal impact on endogenous variables and on hc scores too second we propose a longitudinal analysis period 2000 2004 aimed to investigate how workers earned income growth rates vary over workers educational levels and other personal characteristics the empirical results of both analyses confirm the characteristics of the italian job market denoted by marked inequalities and knowledge regarding the process of school to work transition characterized by a weak incidence of education on longitudinal trajectories of earned income

regional social capital why it matters malecki e j regional social capital why it matters regional studies social capital refers to a culture of interaction among people with productive economic outcomes social capital promotes regional learning both within a region and beyond as it reinforces openness to the ideas of others regional cultures vary in the degree to which people individually and within their organizations trust and interact with one another which is why regional outcomes vary innovation learning and entrepreneurship key processes of regional development take place largely within and among people as members of companies and territorial organizations innovative milieus industrial districts and knowledge economies are among the regions with extraordinary pools of social capital malecki e j

flexibility learning and irreversibility in environmental decisions a bayesian approach the bayes decision is characterized and studied for a two period decision problem involving a proposed resource development project it is assumed that development is irreversible and that expectations about benefits and costs during the second period vary with experiences resulting from the first period action the amount and types of learning achieved depend upon the particular action taken during the first period flexible sequential decision procedures are compared with fixed once and for all decisions it is shown that under this specification optimal development decisions are not necessarily more conservative when a sequential procedure is used the possibility of reneging on a fixed decision is formally specified and studied

good timing the economics of optimal stopping abstract this paper presents an economic interpretation of the optimal stopping of perpetual project opportunities under both certainty and uncertainty prior to stopping the expected rate of return from delay exceeds the rate of interest the expected rate of return from delay is the sum of the expected rate of change in project value and the expected rate of change in the option premium associated with waiting at stopping the expected rate of return from delay has fallen to the rate of interest viewing stopping in this way unifies the theoretical and practical insights of the theory of stopping under certainty and uncertainty

genetic variation in financial decision making individuals differ in how they construct their investment portfolios yet empirical models of portfolio risk typically account only for a small portion of the cross sectional variance this paper asks whether genetic variation can explain some of these individual differences following a major pension reform swedish adults had to form a portfolio from a large menu of funds we match data on these investment decisions with the swedish twin registry and find that approximately 25 of individual variation in portfolio risk is due to genetic variation we also find that these results extend to several other aspects of financial decision making

economic aspects of human cloning and reprogenetics while most discussions of human cloning start and end with ethics this paper analyses the economics of human cloning i analyse the incentives for cloning and its implications for the long run distribution of skills and income i discuss models of human cloning for different motives focusing on those that tend to produce new human beings with improved ability i distinguish three cases cloning as a means of assisted reproduction for infertile couples cloning by fertile couples aimed at producing high ability offspring and finally financially motivated cloning the third case supposes that the creator of a clone can appropriate some fraction of the clone s future income even if this fraction is small the possibility of producing exceptionally talented clones with correspondingly high incomes might make it profitable and thus turn cloning into a form of financial investment an important consequence of these models is that to the extent that ability is genetically determined and cloners prefer to make high ability clones cloning will act as a form of what might be called unnatural selection following standard darwinian logic such selection will tend to increase the proportion of high ability people in society indeed under some assumptions the distribution of ability eventually converges to a mass point at the highest possible ability level under weaker assumptions it is shown that ability reducing genes are eventually eliminated these results do not depend on cloning displacing sexual reproduction or even being widespread they hold even if a small or even negligible number of top ability workers are cloned at a small but not negligible number of copies the paper discusses the plausibility of the models and their results in light on the evidence on marriage markets child selection human assisted reproduction and animal husbandry finally it is shown how the analysis can be used to help formulate policies toward cloning whether they aim at preventing it or managing its external effects gilles saint paul

returns to education evidence from u k twins we use a new sample of uk female identical twins to estimate private economic returns to education we report findings in three areas first we use identical twins to control for family effects and genetic ability bias and the education reported by the other twin to control for schooling measurement error our estimates suggest a return to schooling for uk females of about 7 7 second we investigate within twin pair ability differences by examining within twin pair and between family correlations of education with observable correlates of ability including birthweight ability tests and reading scores our findings suggest lower ability bias in within twin pair regressions than pooled regressions third using data on twins smoking we show smoking reflects family background and using it as an instrument exacerbates ability bias this abstract was borrowed from another version of this item

absorptive capacity and localized spillovers focal firms as technological gatekeepers in industrial districts despite the diffusion of communication tools and boundary spanning technologies knowledge flows in innovation processes retain a distinct localized nature in many industries and geographical clusters emerge as critical areas to foster technological diffusion in this article we focus on the knowledge mediating role as technological gatekeepers of focal firms in industrial districts based on a longitudinal dataset of 720 patents granted by the united states patent and trademark office uspto between 1990 and 2003 to firms in the automatic packaging machinery industrial district in northern italy and controlling for the uneven geographical distribution of patenting activities we show that i firms within the district use local knowledge to a greater extent and more rapidly than knowledge from outside the district ii focal firms use external knowledge to a greater extent than other firms operating in the district and iii other nonfocal firms within the district rely on knowledge generated by focal firms to a greater extent than would be expected given the geographic distribution of innovative activity in the industry implications for research on innovation in localized economic systems and firm level strategic differentiation are discussed copyright 2012 the author 2011 published by oxford university press on behalf of associazione icc all rights reserved oxford university press

peer monitoring and credit markets a major problem for institutional lenders is ensuring that borrowers exercise prudence in the use of the funds so that the likelihood of repayment is enhanced one partial solution is peer monitoring having neighbors who are in a good position to monitor the borrower be required to pay a penalty if the borrower goes bankrupt peer monitoring is largely responsible for the successful financial performance of the grameen bank of bangladesh and of similar group lending programs elsewhere but peer monitoring has a cost it transfers risk from the bank which is in a better position to bear risk to the cosigner in a simple model of peer monitoring in a competitive credit market this article demonstrates that the transfer of risk leads to an improvement in borrowers welfare

human capital vs signalling explanations of wages increases wages by directly increasing the worker s productivity this learning explanation is usually associated with human capital theory however it seems unlikely that learning explains all the wage differences associated with schooling and work history better educated workers are not a random sample of workers they have lower propensities to quit or to be absent are less likely to smoke drink or use illicit drugs and are generally healthier it is unlikely that employers make full use of differences in propensities to quit or to be absent or sick when hiring workers these characteristics are often not directly observed and the americans with disabilities act precludes firms from using either poor health or the likelihood of future sickness as a hiring criterion unless it is directly related to job performance however if low levels of education are associated with these unfavorable employee characteristics and employers are allowed to take education into account when hiring workers we would expect employers to favor better educated workers as a means of reducing their costs of sickness and job turnover in turn students will take these hiring criteria into account when deciding how long to stay in school students will choose a length of schooling to signal their ability to employers and employers will demand a minimum level of schooling

risk sharing role of foreign aid in developing countries abstractthe effects of foreign aid on economic growth have been extensively investigated over the past 40 years however even though foreign aid can be a significant source of insurance against do

inequality and growth why differential fertility matters we argue that inequality and growth are linked through differential fertility and the accumulation of human capital we build an overlapping generations model in which dynasties differ in their initial endowment with human capital growth the income distribution and fertility are endogenous due to a quantiy quality tradeoff families with less human capital decide to have more children and invest less in education when initial inequality is high large fertility differentials lower the growth rate of average human capital since poor families who invest little in education make up a large fraction of the population in the next generation a calibrated model shows that this fertility differential effect is quantitatively important we also provide empirical evidence to confirm the links between inequality differential fertility and growth suggested by the model

birth weight and schooling and earnings estimates from a sample of twins based on analysis of a sample of twins this study suggests that birth weight is not related to levels of schooling that it plays only a minor role in the determination of earnings and that ability differences that are not removed in the within twins model of earnings are not biasing the results in twins studies such as ashenfelter and krueger ashenfelter o krueger a 1994 estimates of the economic return to schooling from a new sample of twins american economic review 84 5 pp 1157 1173 d 2004 elsevier b v all rights reserved

power shifts the dynamics of energy efficiency induced technical change is crucial for tackling the problem of timing in environmental policy however it is by no means obvious that the state has the ability to impose its will concerning technical change on the other relevant actors therefore we conceptualize power in a non linear model with social conflict and induced technical change the model shows how economic growth business cycles and innovation waves interact in the dynamics of energy efficiency we assess three different ways of government control energy taxes energy and labor subsidies and energy caps energy taxes help to select more energy efficient technologies however a successful selection of such technologies presupposes that they are available in the pool of technologies as for energy subsidies their existence helps to explain why in contemporary economies labor productivity grows faster than energy efficiency with an energy cap the social network of the relevant agents may be stabilized via social norms it seems plausible that innovation waves comprise several business cycles and that such a wave is currently in the making proposals to postpone policies for improving energy efficiency increase the risk of energy inefficient lock in effects

on the valuation of uncertainty in welfare analysis thisarticle developsa general model of private and public choice under temporal uncertainty the model incorporatesthe effectsof ris k preferencesand the pros pect of future learning into both the individual and aggregate valuationsof public projects the analys isprovidesnew ins ightson individual valuation itsimplicationsfor benefit cos t analys isand the characterization of paretoefficiency under uncertainty it also resolves some of the confusion in the option value and quasioption value literature private and public decisions typically involve many sources of uncertainty including uncertainty about prices income technology environmental quality health etc temporal uncertainty is also common where some of the risk 1 getsresolved over time due to learning additionally private and public decisions often exhibit some form of irreversibility implying that current choicescan affect the ability of decision makers to be flexible and to adjust their future choices in response to forthcoming information when uncertainty and irreversibility are both present welfare analys isgainscomplexity and importance although considerable progress has been made since weisbrod s seminal article a better understanding of the roles of uncertainty and irreversibility in welfare analys improve our ability aseconomis ts to communicate the importance of risk in project evaluation to public decision makers

is tourism firm competitiveness driven by different internal or external specific factors new empirical evidence from spain abstract the quest to understand the multilevel antecedents of competitiveness has led to a separation of approaches on one side of the question are the environment theories that analyze the structural characteristics of the general and competitive environment on the other side are the resource based view and its extensions that highlight firm specific resources and capabilities as the main basis of firms competitiveness however in recent years the nature of competition and shifting economic conditions have given rise to new theoretical approaches that complement the assumptions underlying both environmental and firm theories specifically this study contributes by examining the regional environment effect the district effect and the strategic group effect through a study of 364 spanish tourism firms this research explores the relative importance of distinct external forces such as the general environment or country effect the regional effect the competitive environment or industry effect the district effect and internal factors such as the firm s tangible resources capabilities and strategy selection the results demonstrate that firms capabilities are more important than environment effects and tangible resources

input use decisions with greater information on crop conditions implications for insurance moral hazard and the environment emerging precision agriculture technologies allow farms to make input decisions with greater information on crop conditions this greater information occurs by providing improved predictions of crop yields using remote sensing and crop simulation models and by allowing farms to apply inputs within the growing season when some crop conditions are already realized we use a stylized model with uncertainty in yield and price to examine how greater information on crop conditions i e a forecast affects input use for insured and uninsured farms we show that moral hazard decreases farms apply more inputs as the forecast accuracy improves when the forecast indicates good yields and vice versa when the forecast indicates bad yields in the long run moral hazard decreases in response to an improvement in forecast accuracy even though moral hazard decreases in the long run indemnity payments are likely to increase in the long run driven by the increase in moral hazard when the forecast indicates bad crop conditions we use the results of our model to discuss the potential impact of different technologies and types of inputs on the federal crop insurance program and the environment

foreign portfolio diversification and risk sharing we investigate income smoothing associated with international portfolio diversification by decomposing the net factor income nfi channel into interests dividends and retained earnings for oecd and eu countries we find that interest receipts and equity dividend payments contribute significantly to absorb domestic income shocks geographically concentrated portfolios and in particular biases toward eu markets have a strong negative effect on the degree of risk sharing

learning and stock effects in environmental regulation the case of greenhouse gas emissions abstract this paper concerns the optimal regulation of greenhouse gases that lead to global climate change in particular we focus on uncertainty and learning which over time resolves uncertainty we present an empirical stochastic model of climate economy interactions and present results on the tension between postponing control until more is known vs acting now before irreversible climate change takes place uncertainty in our model is in the damage caused by global warming the results suggest that a temporary carbon tax may dominate a permanent one because a temporary tax may induce increased flexibility

astronomics in action the graduate earnings premium and the dragon effect in singapore white u s and latin american currencies portray images of national independence heroes singapore s 2 dollar bill the most widely circulated since there is no smaller denomination shows students in a classroom listening to a professor with a university in the background underneath there is just one word education singapore s obsession with education miami herald 8 september 2009 i introduction since the groundbreaking work of mincer 1974 many academics have looked closely at the question of what the return to education might be 1 however because of the lack of data the literature does not have much to say about singapore even though a lot of research has been done for advanced countries throughout the world 2 3 in this paper we employ a recent survey from the singapore national youth council to study one aspect of this topic the return to university education in singapore having a university education is usually perceived to be good for one s career although the extent to which this is true has been a constant point of contention 4 this debate had relied largely on anecdotes instead of econometric research understandably so because data is not easily available therefore this paper hopes to offer some evidence on the causal link between university education and earnings outcome in singapore however identification is a formidable challenge as in any research that aims to estimate the return to education although the positive association between education and earnings is a virtually ubiquitous fact prima facie evidence of income gaps may misrepresent what the true return to education is because individuals tend to make educational choices according to their abilities such income gaps would contain not only the return that is due to education the quantity of interest but also the return on unobserved abilities which is the confounding effect over the years economists have sought to disentangle the causal effect of education from the confounding effect of unobserved abilities in the data but the existing estimation approaches are not easily adaptable here for example methods that employ within twin comparisons or changes in compulsory schooling laws cannot be implemented owing to data limitations and the lack of important schooling reforms in singapore 5 in fact the dataset used here was compiled for a different purpose than economics which is to provide a better understanding of singapore s youths from a sociological perspective given these issues a new estimation approach has to be considered in this paper we propose to exploit a consequence li liu and zhang 2012 of chinese traditions generating the so called dragon effect to study the causal link between university education and income in singapore chinese is the largest ethnic group and malays indians and eurasians are the main ethnic minorities according to chinese traditions there are 12 creatures in the chinese zodiac where each represents a lunar year in a 12 year cycle among them the dragon is the most auspicious creature and babies born in a dragon year are believed to be superior 6 because of this conviction the dragon year has seen upswings in the rate of birth not just in singapore but also in places where chinese culture is prevalent 7 for example figure 1 plots the birth rate from 1970 in singapore based on resident women aged between 15 and 49 8 while the fertility rate was plunging early on it did increase momentarily during the dragon year of 1976 there was another sharp increase in 1988 9 and then in 2000 which marks the highly auspicious year of the golden dragon figure 1 omitted the positive relationship between the birth rate and the dragon year provides the rationale behind the identification strategy used here as the dragon cohort is larger than usual competition for entry into university would be more intense leading to what is known as the dragon effect

how much difference is there between industrial district firms a net value creation approach abstract we argue that industrial district firms possess a number of shared resources that explain the competitive superiority of these firms these factors include common reputation intensity of exchange and combination of resources and participation of the local institutions using these shared resources we aim to address an unsolved question in the industrial district literature namely the internal heterogeneity of the clustered firms our empirical research drew upon a sample of 288 spanish manufacturing firms belonging to industrial districts findings suggest that even assuming a certain degree of homogeneity among internal district firms they develop their own particular relationships and networks and as a result exploitation of the shared resources is irregular these differences can therefore be used to explain the differences in value creation among firms

information and the concept of option value this paper examines the arrow fisher henry concept of option value and analyzes its properties including its relationship to the value of information and the effects of increasing uncertainty about the future consequences of irreversible development it is shown that this option value is distinct from but bounded by the value of information in the overall decision problem also it is distinct from a concept of option value that appears in b s bernanke quart j econom 98 85 106 1983 however when there is a continuum of development levels rather than a binary choice between full development and no development some of these conclusions need to be modified

where has all the education gone cross national data show no association between increases in human capital attributable to the rising educational attainment of the labor force and the rate of growth of output per worker this implies that the association of educational capital growth with conventional measures of total factor production is large strongly statistically significant and negative these are on average results derived from imposing a constant coefficient however the development impact of education varied widely across countries and has fallen short of expectations for three possible reasons first the institutional governance environment could have been sufficiently perverse that the accumulation of educational capital lowered economic growth second marginal returns to education could have fallen rapidly as the supply of educated labor expanded while demand remained stagnant third educational quality could have been so low that years of schooling created no human capital the extent and mix of these three phenomena vary from country to country in explaining the actual economic impact of education or the lack thereof

investment and the banking system a kaleckian approach for regions in brazil this paper analyzes the effects of the regional distribution of the banking system on investment rates in brazil the investigation relies on a perspective whereby the role of external funds in ind

the effects of human capital interventions on entrepreneurial performance in industrialized countries this paper provides a systematic review of studies on the effects of human capital interventions on entrepreneurial performance in industrialized countries we identify 21 experimental and quasi experimental studies published before september 2018 these studies examine the effects of business training formal education and entrepreneurship education their performance outcomes include firm profits firm size and entrepreneurial earnings the main finding across these studies is that these interventions do not have statistically significant effects formal education is the only exception showing positive effects on firm profits and entrepreneurial earnings yet these effects are small in magnitude evidence is inconclusive regarding effect duration these findings stand in stark contrast to correlational studies which tend to find large positive correlations between human capital interventions and entrepreneurial performance we therefore conclude that correlational studies tend to overestimate the benefits of human capital interventions moreover our estimates show that the interventions are associated with moderately low additionality

voluntary conservation of endangered species when does no regulatory assurance mean no conservation abstract voluntary conservation agreements are becoming increasingly important in implementing the endangered species act on private land we analyze when such agreements arise and what level of conservation they generate in the presence of uncertainty about future conservation benefits and irreversibility of habitat loss and species extinction our results suggest that the likelihood of an agreement and the resulting conservation levels depend on the background threat of regulation the cost advantage offered by voluntary agreements and the availability of assurances regarding future regulation under conditions likely to hold in practice conservation agreements that offer assurances may generate higher levels of conservation and higher net social benefits than agreements that do not offer assurances however the resulting level of conservation will not be optimal and may be lower than that attainable under regulation

outsourcing decisions product innovation and the spatial dimension evidence from the spanish footwear industry recent studies in developed countries frequently emphasise the importance of outsourcing as a strategy for manufacturing industries to survive however there is little qualitative evidence that specifically describes outsourcers in mature industries with competitive problems particularly in southern europe this paper attempts to fill this gap by investigating the distinctive traits of firms located in the most important spanish footwear industrial districts from a sample of 401 spanish firms surveyed in january and february 2006 it was found that size design and product innovation prior institutional networks and location in specific industrial districts favour the development of outsourcing strategies by contrast clients prior networks are negatively related with contracting out productive activities these results are relevant in several dimensions however the positive impact of some districts in the externalisation decision should be specifically mentioned such evidence seems to confirm t