rising inequality and neighbourhood mixing in us metro areas abstractsuperstar cities with high paying creative class jobs venture capital and innovation are thought to be more unequal we analyze mixing in neighbourhoods by income education and occupatio

banking development socioeconomic structure and income inequality abstract using rich unique data from the italian local credit markets provinces this paper investigates the impact of local banking development on income inequality and the role of the socioeconomic structure in this link exploiting the italian historical banking regulation to instrument for the local presence of bank branches we find that local banking development mitigates income inequality however the finance inequality nexus manifests itself only in relatively advanced areas when we study the structural channels of influence we uncover evidence that banking development can reduce inequality by affecting geographical mobility and urbanization while it has modest effects through the development of material infrastructures and human capital

skill biased technological change and rising wage inequality some problems and puzzles the recent rise in wage inequality is usually attributed to skill biased technical change sbtc associated with new computer technologies we review the evidence for this hypothesis focusing on the implications of sbtc for overall wage inequality and for changes in wage differentials between groups a key problem for the sbtc hypothesis is that wage inequality stabilized in the 1990s despite continuing advances in computer technology sbtc also fails to explain the evolution of other dimensions of wage inequality including the gender and racial wage gaps and the age gradient in the return to education

the comparative advantage of cities abstract what determines the distributions of skills occupations and industries across cities we develop a theory to jointly address these fundamental questions about the spatial organization of economies our model incorporates a system of cities their internal urban structures and a high dimensional theory of factor driven comparative advantage it predicts that larger cities will be skill abundant and specialize in skill intensive activities according to the monotone likelihood ratio property we test the model using data on 270 us metropolitan areas 3 to 9 educational categories 22 occupations and 19 industries the results provide support for our theory s predictions

skills in the city this paper documents the allocation of skills across cities and estimates the impact of agglomeration on the hedonic prices of worker skills we find that large cities are more skilled than are small cities but only to a modest degree we also show that the increase in productivity associated with agglomeration as measured by the urban wage premium is larger for workers with stronger cognitive and people skills in contrast motor skills and physical strength are not rewarded to a greater degree in large cities urbanization thus enhances thinking and social interaction rather than physical abilities these results are robust to a variety of estimation strategies including using nlsy variables that control for worker quality and a worker msa fixed effect specification

the income inequality nexus in a developed country small scale regional evidence from austria abstractthe income inequality nexus in a developed country small scale regional evidence from austria regional studies this paper analyses the relationship between regional inequality and average income in a small scale framework for austria the empirical findings are based on a novel inequality database generated from individual wage tax information at the municipality level this study researches the magnitude of regional spillovers of income and inequality using spatial econometric methods the results show a pronounced positive relation between regional income levels and inequality where especially high income municipalities exhibit a large spread in the income distribution furthermore it shows that higher levels of inequality are associated with income gains at the top of the distribution

counterfactual decomposition of changes in wage distributions using quantile regression we propose a method to decompose the changes in the wage distribution over a period of time in several factors contributing to those changes the method is based on the estimation of marginal wage distributions consistent with a conditional distribution estimated by quantile regression as well as with any hypothesized distribution for the covariates comparing the marginal distributions implied by different distributions for the covariates one is then able to perform counterfactual exercises the proposed methodology enables the identification of the sources of the increased wage inequality observed in most countries specifically it decomposes the changes in the wage distribution over a period of time into several factors contributing to those changes namely by discriminating between changes in the characteristics of the working population and changes in the returns to these characteristics we apply this methodology to portuguese data for the period 1986 1995 and find that the observed increase in educational levels contributed decisively towards greater wage inequality copyright 2005 john wiley sons ltd

empirically driven hierarchical classification of stock keeping units this paper proposes a hierarchical multi criteria classification method developed for inventory management purposes and applied in a case study of the spare parts business of a household appliance manufacturer the classification method is built on the basis of six dimensions resulting in 12 different classes of spare parts for which differentiated forecasting and inventory policies are proposed and tested the results of our simulation study demonstrate the reduction of the total logistics costs by about 20 whilst still achieving the specified target service level for each class even more importantly the proposed approach is simple enough to be understood and applied by company managers thus increasing the probability of its adoption in the same or similar fashion in other real world settings

the endogenous relationship between innovation and diversification and the impact of technological resources on the form of diversification abstract this research has endeavoured to build on earlier research on the relationship between a firm s technological resources and the direction of its diversification by trying to confirm the endogeneity of this relationship and by addressing the influence of innovation on the choice of the mode of diversification based on a sample of spanish firms our results suggest that innovation drives diversification but not the reverse the second important finding of this research is the empirical confirmation that knowledge assets are not related to the diversification mode

inequality and city size between 1979 and 2007 a strong positive monotonic relationship between wage inequality and city size has developed this paper investigates the links between this emergent city size inequality premium and the contemporaneous nationwide increase in wage inequality after controlling for the skill composition of the workforce across cities of different sizes we show that at least 23 percent of the overall increase in the variance of log hourly wages in the united states from 1979 to 2007 is explained by the more rapid growth in the variance of log wages in larger locations relative to smaller locations this influence occurred throughout the wage distribution and was most prevalent during the 1990s more rapid growth in within skill group inequality in larger cities has been by far the most important force driving these city size specific patterns in the data differences in the industrial composition of cities of different sizes explain up to one third of this city size effect these results suggest an important role for agglomeration economies in generating changes in the wage structure during the study period

cheap children and the persistence of poverty this paper develops a theory of fertility that offers an explanation for the persistence of poverty within and across countries if educated individuals have a comparative advantage in raising educated children then parental fertility choice is shown to give rise to a poverty trap in which the poor choose high fertility rates with low investment in child quality moreover the impact of child quality choice on economic performance is amplified by the diluting effect of higher fertility on physical capital accumulation the theory proposes insights regarding the effects of inequality globalisation and life expectancy on economic growth and demographic transitions this paper develops a theory of fertility and child educational choice that offers an explanation for the persistence of poverty within and across countries the joint determination of the quality education and quantity of children in a household is studied under the key assumption that individuals productivity as teachers increases with their own human capital in contrast the minimum time cost associated with raising a child regardless of the child s quality the quantity cost is not affected by parental education as a result the price of child quantity relative to the price of child quality increases with individuals wages in particular for low wage individuals for whom the opportunity cost of time is low children of minimal quality are cheap this assumption therefore generates a comparative advantage for the poor in child quantity whereas high wage educated individuals have a comparative advantage in raising quality children consistent with the well known evidence poor households thus choose relatively high fertility rates with relatively low investment in their offspring s education and therefore their offspring are poor as well in contrast high income families choose low fertility rates with high investment in education and therefore high income persists in the dynasty evidence from the us provided by hanushek 1992 suggests that a trade off between quantity and quality of children does indeed exist hanushek argues that movements in family size could explain over half the variance in some test scores and that the elasticity of achievements with respect to the number of children in the family is 0 03 implying that the annual achievement growth of each child in a family will fall about 2 when a second child is added and about 0 5 when a sixth child is added 1

optimal patent breadth and length with costly imitation abstract patent breadth is defined using the number of potential entrants which enter an industry it is shown that optimal patent design may be broad and short lived or narrow and infinitely lived depending on the market structure assumed and the properties of the demand function in the presence of costly imitation and endogenous entry it is shown that optimal patent design may be either broad narrow or of intermediate breadth depending on the properties of the aggregate imitation cost function

intelligence social mobility and growth this study develops a model where the allocation of human resources intergenerational social mobility and technological growth are jointly determined high growth endogenously increases the equilibrium return to innate cognitive ability and makes the allocation of individuals depend more on innate ability and less on social background a social allocation based on innate ability and high growth will thus reinforce each other implying the possibility of multiple endogenous growth equilibria

immigration and inequality immigration is often viewed as a proximate cause of the rising wage gap between highand low skilled workers nevertheless there is controversy over the appropriate theoretical and empirical framework for measuring the presumed effect and over the precise magnitudes involved this paper offers an overview and synthesis of existing knowledge on the relationship between immigration and inequality focusing on evidence from cross city comparisons in the u s while some researchers have claimed that a cross city research design is inherently flawed i argue that the evidence from cross city comparisons is remarkably consistent with recent findings based on aggregate time series data in particular cross city and aggregate time series comparisons provide support for three key conclusions 1 workers with below high school education are perfect substitutes for those with a high school education 2 high school equivalent and college equivalent workers are imperfect substitutes with an elasticity of substitution on the order of 2 3 within education groups immigrants and natives are imperfect substitutes together these results imply that the average impacts of recent immigrant inflows on the relative wages of u s natives are small the effects on overall wage inequality including natives and immigrants are larger reflecting the concentration of immigrants in the tails of the skill distribution and higher residual inequality among immigrants than natives even so immigration accounts for a small share 5 of the increase in u s wage inequality between 1980 and 2000

selection in initial and return migration evidence from moves across spanish cities this paper investigates the sorting of more productive workers into denser cities using administrative data for spain that fol low individuals continuously throughout their working lives migrants who move to denser cities are positively selected in terms of educa tion occupational skills and individual productivity as proxied by pre migration position in the local earnings distribution however not everyone is able to benefit equally from denser cities and this leads to a second round of sorting returnees are not only ex ante less productive than permanent migrants but are also those who following the first move have least boosted up their earnings in denser cities

mismeasurement of usual hours worked in the census and acs recent decennial censuses and the american community survey acs collect data that permit construction of average hourly wage rates however reports concerning usual hours worked during the past year contain errors that create incredible implied wages for part time workers

income distribution and macroeconomics this paper analyzes the role of wealth distribution in macroeconomics through investment in human capital it is shown that in the presence of credit markets imperfections and indivisibilities in investment in human capital the initial distribution of wealth affects aggregate output and investment both in the short and in the long run as there are multiple steady states this paper therefore provides an additional explanation for the persistent differences in per capita output across countries furthermore the paper shows that cross country differences in macroeconomic adjustment to aggregate shocks can be attributed among other factors to differences in wealth and income distribution across countries

setting stock levels for wholesaling performance measures and conflict of objectives between supplier and stockist abstract the situation considered is that where a sales outlet holds a stock of goods for sale which are topped up by regular weekly deliveries demand is highly variable and ranges from high to very low over the many items held in stock an appropriate stock system to use in these circumstances is an order up to policy but the problem is to set the right order up to levels for each item items which experience low demand require particular care the mathematical model used for setting stock levels for these items has to allow for the possibility of stockouts occuring before the review time and not only in the period from review to delivery the paper consideres various measures which are used for assessing the performance of sales outlets and the implications of these measures for setting stock levels some measures are shown to be very sensitive to the level of sales and also need to be used with care when making interbranch comparisons a consideration of performance measures also brings out the potential for conflict of interest between supplier and stockist

international capacity choice and national market games abstract international trade is modelled as a two stage game between firms in different countries at the first stage firms choose their capacity and at the second stage play a separate price game in each national market given their worldwide capacity it is established that firms use capacity strategically in order to manipulate the distribution of rivals output between markets the volume of intra industry trade is intermediate between the cases of integrated and segmented market cournot equilibria countries gain from small import tariffs and export subsidies but these gains are less than in the segmented market cournot equilibrium case

intermittent demand forecasts with neural networks intermittent demand appears when demand events occur only sporadically typically such time series have few observations making intermittent demand forecasting challenging forecast errors can be costly in terms of unmet demand or obsolescent stock intermittent demand forecasting has been addressed using established forecasting methods including simple moving averages exponential smoothing and croston s method with its variants this study proposes a neural network nn methodology to forecast intermittent time series these nns are used to provide dynamic demand rate forecasts which do not assume constant demand rate in the future and can capture interactions between the non zero demand and the inter arrival rate of demand events overcoming the limitations of croston s method in order to mitigate the issue of limited fitting sample which is common in intermittent demand the proposed models use regularised training and median ensembles over multiple training initialisations to produce robust forecasts the nns are evaluated against established benchmarks using both forecasting accuracy and inventory metrics the findings of forecasting and inventory metrics are conflicting while nns achieved poor forecasting accuracy and bias all nn variants achieved higher service levels than the best performing croston s method variant without requiring analogous increases in stock holding volume therefore nns are found to be effective for intermittent demand applications this study provides further arguments and evidence against the use of conventional forecasting accuracy metrics to evaluate forecasting methods for intermittent demand concluding that attention to inventory metrics is desirable

forecasting and stock control a study in a wholesaling context wholesalers add value to the products they deal with by essentially bringing them closer to the end consumers in that respect the effective control of stock levels becomes an important measure of operational performance especially in the context of achieving high customer service levels in this paper we address issues pertinent to forecasting and inventory management in a wholesaling environment and discuss the recommendations proposed in such a context in a case study organization our findings demonstrate the considerable scope that exists for improving current practices and offers insights into possible managerial issues

learning by working in big cities individual earnings are higher in bigger cities we consider three reasons spatial sorting of initially more productive workers static advantages from workers current location and learning by working in bigger cities using rich administrative data for spain we find that workers in bigger cities do not have higher initial ability as reflected in fixed effects instead they obtain an immediate static premium and accumulate more valuable experience the additional value of experi ence in bigger cities persists after leaving and is stronger for those with higher initial ability this explains both the higher mean and greater dispersion of earnings in bigger cities

understanding the evolution of the us wage distribution a theoretical analysis in this paper we propose an analytically tractable overlapping generations model of human capital accumulation and study its implications for the evolution of the us wage distribution from 1970 to 2000 the key feature of the model and the only source of heterogeneity is that individuals differ in theirabilitytoaccumulatehumancapital therefore wageinequalityresultsonlyfromdifferencesin human capital accumulation we examine the response of this model to skill biased technical change sbtc theoretically we show that in response to sbtc the model generates behavior consistent with some prominent trends observed in the us data including i a rise in overall wage inequality both in the short run and long run ii an initial fall in the education premium followed by a strong recovery leading to a higher premium in the long run iii the fact that most of this fall and rise takes place among younger workers iv a rise in within group inequality v stagnation in median wage growth and a slowdown in aggregate labor productivity and vi a rise in consumption inequality that is much smaller than the rise in wage inequality these results suggest that the heterogeneity in the ability to accumulate human capital is an important feature for understanding the effects of sbtc and interpreting the transformation of the us labor markets since the 1970s jel e21 e24 j24 j31

unintended consequences on gender diversity of high tech growth and labor market polarization abstract there has been considerable media coverage highlighting the lack of gender diversity in silicon valley stressing the relatively low participation of women in the high tech economy austin offers a unique case for testing whether similar gender issues characterized other high tech regions because the city has historically benefited from the expansion of silicon valley s large high tech firms since the 1980s the gender biased business practices identified in silicon valley firms may have been transferred to their branch plants in austin our analysis shows women s losses in middle skill occupation employment shares were concentrated in the low tech industry and were partially offset by job share gains in high skill occupations in the same sector between 1980 and 2015 men s losses in middle skill occupation job share were also mainly concentrated in the low tech sector but were partially offset by employment share gains in high skill occupations only in the high tech industry during this period women made large gains in relative real median wages only in high skill occupations in the high tech industry while their relative real median wages in other skill occupations and in the low tech industry stagnated around zero during this period men s gains in relative median wages were also concentrated only in the high tech industry but were less than half of women s and were negative between 10 and 21 percent in other occupations in the high tech industry and across all occupations in the low tech industry as noted in previous studies the impact of job polarization is not well understood across sectors and gender this study finds the high tech industry in austin has had unintended consequences in terms of job polarization across gender providing relatively fewer job opportunities in high skill occupations to women than men but offering much higher gains in relative real median wages to women than men males also found relatively more job opportunities in high skill occupations in the high tech industry than women but experienced only half of women s gains in relative median wages in this industry between 1980 and 2015

does traffic congestion reduce employment growth abstract this paper examines the impact of traffic congestion on employment growth in large u s metropolitan areas an historic highway plan and political variables serve as instruments for endogenous congestion the results show that high initial levels of congestion dampen subsequent employment growth this finding suggests that increasing the efficiency of public infrastructure can spur local economies counterfactual estimates show that the employment growth returns from modest capacity expansion or congestion pricing are substantial

forecasting with multivariate temporal aggregation the case of promotional modelling demand forecasting is central to decision making and operations in organisations as the volume of forecasts increases for example due to an increased product customisation that leads to more skus being traded or a reduction in the length of the forecasting cycle there is a pressing need for reliable automated forecasting conventionally companies rely on a statistical baseline forecast that captures only past demand patterns which is subsequently adjusted by human experts to incorporate additional information such as promotions although there is evidence that such process adds value to forecasting it is questionable how much it can scale up due to the human element instead in the literature it has been proposed to enhance the baseline forecasts with external well structured information such as the promotional plan of the company and let experts focus on the less structured information thus reducing their workload and allowing them to focus where they can add most value this change in forecasting support systems requires reliable multivariate forecasting models that can be automated accurate and robust this paper proposes an extension of the recently proposed muliple aggregation prediction algorithm mapa which uses temporal aggregation to improve upon the established exponential smoothing family of methods mapa is attractive as it has been found to increase both the accuracy and robustness of exponential smoothing the extended multivariate mapa is evaluated against established benchmarks in modelling a number of heavily promoted products and is found to perform well in terms of forecast bias and accuracy furthermore we demonstrate that modelling time series using multiple temporal aggregation levels makes the final forecast robust to model misspecification

public schooling college subsidies and growth abstract how does the mix of public education expenditures across primary and secondary k 12 education and post secondary college education influence economic growth to address this i build an overlapping generations endogenous growth model human capital is accumulated through compulsory k 12 education and through optional college education government uses tax revenue to provide quality in k 12 schooling and to subsidize college tuition when total expenditures are small all funds should provide k 12 quality when expenditures are above a critical value a positive share should subsidize tuition the share should increase with total expenditures and with the degree of complementarity of human capital accumulated through the two types of education also increased education spending is more likely to increase growth when a larger share subsidizes tuition

urban development excessive entry of firms and wage inequality in developing countries this paper examines the short and long term effects of urbanisation via favourable urban development policies on income distribution and social welfare for a developing country in which the urban manufacturing sector is characterised by imperfect competition and free entry urbanisation shifts rural workers to the highly productive urban sector while causing production in urban firms to expand because of scale economies however urbanisation may worsen wage inequality between skilled and unskilled labour in the short term in the long term urbanisation can attract new firms to the urban sector and favourable urban development policies may result in excessive entry of firms which can amplify wage inequality in the economy this entry amplifying effect is confirmed empirically especially for low and lower middle income countries if the entry effect is not considered the impact of urbanisation on wage inequality could be understated by 13 for low and lower middle income countries

another look at estimators for intermittent demand abstract in this paper we focus on forecasting for intermittent demand data we propose a new aggregation framework for intermittent demand forecasting that performs aggregation over the demand volumes in contrast to the standard framework that employs temporal over time aggregation to achieve this we construct a transformed time series the inverse intermittent demand series the new algorithm is expected to work best on erratic and lumpy demand as a result of the variance reduction of the non zero demands the improvement in forecasting performance is empirically demonstrated through an extensive evaluation in more than 8000 time series of two well researched spare parts data sets from the automotive and defence sectors furthermore a simulation is performed so as to provide a stock control evaluation the proposed framework could find popularity among practitioners given its suitability when dealing with clump sizes as such it could be used in conjunction with existing popular forecasting methods for intermittent demand as an exception handling mechanism when certain types of demand are observed

intermittent demand linking forecasting to inventory obsolescence the standard method to forecast intermittent demand is that by croston this method is available in erp type solutions such as sap and specialised forecasting software packages e g forecast pro and often applied in practice it uses exponential smoothing to separately update the estimated demand size and demand interval whenever a positive demand occurs and their ratio provides the forecast of demand per period the croston method has two important disadvantages first and foremost not updating after many periods with zero demand renders the method unsuitable for dealing with obsolescence issues second the method is positively biased and this is true for all points in time i e considering the forecasts made at an arbitrary time period and issue points only i e considering the forecasts following a positive demand occurrence only the second issue has been addressed in the literature by the proposal of an estimator syntetos boylan approximation sba that is approximately unbiased in this paper we propose a new method that overcomes both these shortcomings while not adding complexity different from the croston method the new method is unbiased for all points in time and it updates the demand probability instead of the demand interval doing so in every period the comparative merits of the new estimator are assessed by means of an extensive simulation experiment the results indicate its superior performance and enable insights to be gained into the linkage between demand forecasting and obsolescence

finance inequality nexus the long and the short of it financial development affects income inequality differently in the short and in the long term investigating oecd countries from 1870 2011 we find in the short run an improvement in financial development tends to reduce inequality while in the long run more finance contributes to more inequality the short run effect concurs with theories advocating financial development increases the availability of financial services primarily for the poor however this effect becomes nil within a few years results thus imply that policies aimed at reducing inequality through improving access of the poor to finance need to be carefully designed to ensure longevity of impact

education technologies wages and technological progress abstract we analyze the worker s incentives to acquire skills under technological progress when the costs of education are endogenous and depend on the wage distribution we show that the agent s intergenerational elasticity of substitution plays then a relevant role in determining how incentives and the long run wage distribution react to technological progress moreover whenever poverty traps of unskilled workers exist higher rates of technological progress can even decrease the incentives of low skill workers to acquire skills we also analyze the effects of educational subsidies in contrast with previous analytical findings we obtain that subsidies always decrease the long run skill premium finally we study the efficiency of the resulting competitive equilibria

adapting wright s modification of holt s method to forecasting intermittent demand abstract the challenge of accurately forecasting demand for spare parts is due to the intermittent nature of their demand this study compares a recent modification of croston s method and a method based on holt s double exponential smoothing taking the firm s competitive priorities into consideration wright s modification of holt s method is presented as a viable alternative when forecasting demand for spares especially when trend is present results indicate that firms focusing on minimizing inventory levels as a priority should consider forecasting using the modified croston s method if their priority is high customer service then the modified holt s method is superior

understanding the city size wage gap in 2000 wages of full time full year workers were more than 30 percent higher in metropolitan areas of over 1 5 million people than rural areas the monotonic relationship between wages and city size is robust to controls for age schooling and labor market experience in this paper we decompose the city size wage gap into various components we propose an on the job search model that incorporates latent ability search frictions firm worker match quality human capital accumulation and endogenous migration between large medium and small cities counterfactual simulations of the model indicate that variation in returns to experience and differences in wage intercepts across location type are the most important mechanisms contributing to the overall city size wage premium steeper returns to experience in larger cities is more important for college graduates while differences in wage intercepts is more important for high school graduates sorting on unobserved ability within education group and differences in labor market search frictions and distributions of firm worker match quality contribute little or slightly negatively to observed city size wage premia in both samples

the short run relationship between inequality and growth evidence from oecd regions during the great recession abstractthis paper provides evidence on the relationship between income inequality and economic growth in organisation for economic co operation and development oecd regions during the decade 2003 13 it combines household survey data and macroeconomic databases covering over 200 comparable regions in 15 oecd countries the econometric results based on two alternative sets of instruments highlight a general negative association between inequalities and economic growth since the start of the economic crisis this relationship is sensitive to the type of urban structure higher inequalities seem to be more detrimental for growth in regions characterized by medium to large sized cities while regions characterized by small cities and rural areas are less affected

on the bias of intermittent demand estimates forecasting and inventory control for intermittent demand items has been a major problem in the manufacturing and supply environment croston operational research quarterly 23 1972 289 proposed a method according to which intermittent demand estimates can be built from constituent events croston s method has been reported to be a robust method but has shown more modest benefits in forecasting accuracy than expected in this research one of the causes of this unexpected performance has been identified as a first step towards improving croston s method certain limitations are identified in croston s approach and a correction in his derivation of the expected estimate of demand per time period is presented in addition a modification to his method that gives approximately unbiased demand per period estimates is introduced all the conclusions are confirmed by means of an extended simulation experiment where croston s and revised croston s methods are compared the forecasting accuracy comparison corresponds to a situation of an inventory control system employing a re order interval or product group review

survival of the fittest in cities urbanisation and inequality we develop a framework that integrates natural advantage agglomeration economies and firm selection to explain why large cities are both more productive and more unequal than small towns our model highlights complementarities among those factors and matches a number of key stylised facts about cities a larger city size increases productivity via selection and higher urban productivity provides incentives for rural urban migration tougher selection increases the returns to skills and earnings inequality in cities we illustrate a multi city version of the model numerically and explore the formation of new cities the growth of existing cities and changes in income inequality

imitation costs and patents an empirical study it has long been recognised that the costs of imitating new products have an important effect on the incentives for innovation in a market economy as arrow i962 and others have pointed out if firms can imitate an innovation at a cost that is substantially below the cost to the innovator of developing the innovation there may be little or no incentive for the innovator to carry out the innovation in their discussions of the innovation process economists frequently have called attention to the major role played by the costs of imitation but there has been little or no attempt to measure these costs to test various hypotheses concerning the factors influencing them or to estimate their effects in this paper we report some findings of what seems to be the first study of this topic in addition we present data regarding the effects of patents on imitation costs and on the rate of innovation

the race between man and machine implications of technology for growth factor shares and employment we examine the concerns that new technologies will render labor redundant in a framework in which tasks previously performed by labor can be automated and new versions of existing tasks in which labor has a comparative advantage can be created in a static version where capital is fixed and technology is exogenous automation reduces employment and the labor share and may even reduce wages while the creation of new tasks has the opposite effects our full model endogenizes capital accumulation and the direction of research towards automation and the creation of new tasks if the long run rental rate of capital relative to the wage is sufficiently low the long run equilibrium involves automation of all tasks otherwise there exists a stable balanced growth path in which the two types of innovations go hand in hand stability is a consequence of the fact that automation reduces the cost of producing using labor and thus discourages further automation and encourages the creation of new tasks in an extension with heterogeneous skills we show that inequality increases during transitions driven both by faster automation and introduction of new tasks and characterize the conditions under which inequality is increasing or stable in the long run

the accuracy of a modified croston procedure a modified croston procedure to forecast intermittent demand is reviewed the modified procedure published in this journal in 2004 consists of a new method for estimating the mean demand and a smoothing method for estimating the variance of the forecasted demand rate it is found that the smoothed variance estimate is based on an invalid measure of forecast accuracy moreover it is shown that the method of forecasting mean demand produces biased forecasts the accuracy of this method is assessed using simulated data and the mean square error measure and compared with croston s method and single exponential smoothing it is found that croston s method is generally more accurate than its modification particularly for strongly intermittent series

the economics of product patents this paper develops a model of product patents in which the patent changes the nature of market entry behavior rather than preventing entry entirely the model incorporates three levels of action namely the innovator s patenting decision the potential entrant s location decision and possible court action the analysis demonstrates how the characteristics of the patents system and the enforcement framework can influence rivals variety choices and thus the market equilibrium it also considers how the system can in principle be adjusted to improve social welfare copyright 1990 by american economic association

identifying human capital externalities theory with applications the identification of aggregate human capital externalities is still not fully understood the existing mincerian approach confounds positive externalities with wage changes due to a downward sloping demand curve for human capital as a result the mincerian approach yields positive externalities even when wages equal marginal social products we propose an approach that identifies human capital externalities whether or not aggregate demand for human capital slopes downward another advantage of our approach is that it does not require estimates of the individual return to human capital applications to u s cities and states between 1970 and 1990 yield no evidence of significant average schooling externalities copyright 2006 wiley blackwell

how broad should the scope of patent protection be i explore the trade off between a patent s length that is its lifetime and its width that is its scope of coverage a wider patent generally reduces the distortion of consumers choices between the patented brand of the product and unpatented lower priced varieties sold by competitors but also permits higher prices which increase relative to profits the deadweight losses from consumers switching consumption out of the product class i show under what conditions infinitely lived but very narrowly focused patents are the socially efficient way to reward innovation and under what conditions very short lived but very broad patents are optimal

differences and changes in wage structures preface introduction and summary richard b freeman lawrence f katz 1 a comparison of changes in the structure of wages in four oecd countries lawrence f katz gary w loveman david g blanchflower 2 international differences in executive and managerial compensation john m abowd michael l bognanno 3 the gender earnings gap some international evidence francine d blau lawrence m kahn 4 international wage curves david g blanchflower andrew j oswald 5 the changing structure of male earnings in britain 1974 1988 john schmitt 6 real wages employment and wage dispersion in u s and australian labor markets robert g gregory francis vella 7 labor markets and economic growth lessons from korea s industrialization 1970 1990 dae il kim robert h topel 8 wage differentials in italy market forces institutions and inflation christopher l erickson andrea c ichino 9 the swedish wage structure the rise and fall of solidarity wage policy per anders edin bertil holmlund 10 getting together and breaking apart the decline of centralized collective bargaining richard b freeman robert s gibbons 11 earnings inequality in germany katharine g abraham susan n houseman 12 a comparative analysis of east and west german labor markets before and after unification alan b krueger jorn steffen pischke contributors author index subject index

ability biased technological transition wage inequality and economic growth thispaper develops a growthmodel characterizedbyability biasedtechnological transition in which the evolution of technology education attainment and wage inequality is consistent with the observed pattern in the united states and other advanced countries over the past several decades it argues that an increase in the rate of technological progress raises the return to ability and simultaneously generates an increase in wage inequality between and within groups of skilled and unskilled workers an increase in average wages of skilled workers a temporary decline in average wages of unskilled workers an increase in education and a productivity transitory slowdown

the effects of integrating management judgement into intermittent demand forecasts empirical research suggests that quantitatively derived forecasts are very frequently judgementally adjusted nevertheless little work has been conducted to evaluate the performance of these judgemental adjustments in a practical demand sales context in addition the relevant analysis does not distinguish between slow and fast moving items currently there are neither conceptual developments nor empirical evidence on the issue of integrating judgements and statistical forecasts for slow intermittent demand items moreover no results have ever been reported on the stock control implications of these human judgements our work analyses monthly intermittent demand forecasts for the uk branch of a major international pharmaceutical company the company relies upon a commercially available statistical forecasting system to produce forecasts that are subsequently judgementally adjusted based on marketing intelligence gathered by the company forecasters the benefits of the intervention are evaluated by comparing the actual sales to system and final forecasts using both forecast accuracy and inventory control accuracy implication metrics our study allows insights to be gained on potential improvements to intermittent demand forecasting processes and subsequently the design effectiveness of forecasting support systems

lumpy demand forecasting using neural networks abstract the current study applies neural network nn modeling in forecasting lumpy demand it is to the best of our knowledge the first such study our study compares the performance of nn forecasts to those using three traditional time series methods single exponential smoothing croston s method and the syntetos boylan approximation we find nn models to generally perform better than the traditional methods using three different performance measures we also independently validate earlier findings that the syntetos boylan approximation performs better than the croston s and single exponential smoothing methods in lumpy demand forecasting

forecasting method for noisy demand abstract exponential smoothing methods are very commonly used for forecasting demand regarding the process of forecasting demand the main approach towards the selection and optimisation of alternative methods relates to the minimisation of forecast error measures such as the mean square error mse with regard to pegels classification of usage of proper forecasting methods hw methods additive and multiplicative are appropriate for demand with trend and seasonality which corresponds to b 2 and b 3 but hw methods are not accurate enough for demand with large noise that is often a property of real data in this paper we present improved an hw method for demand with noise and we demonstrate that a reduction in forecast error mse can be reached from the results we prove that the proposed method is more accurate than the existing ones and that it is the proper choice for forecasting noisy demand furthermore we show that essential reduction of supply chain costs can be achieved if we use improved the hw method for joined optimisation

firm heterogeneity in capital labour ratios and wage inequality author s leonardi marco abstract this paper documents the increasing dispersion of capital labor ratios across firms in the us and provides some empirical evidence of a positive correlation at the two digit industry level between the dispersion of capital labor ratios across firms and residual wage inequality to explain this empirical fact the paper adopts a search model where firms differ in their optimal capital investment the exogenous decline in the relative price of equipment capital makes the distributions of capital labor ratios more dispersed in a frictional labor market this force generates wage dispersion among identical workers ols estimates of the relationship between capital dispersion and the relative price of equipment capital support the main hypothesis of the model

effects of correlation on intermittent demand forecasting and stock control abstract this study investigates the effects of three different types of correlation on forecasting and stock control of intermittent demand items applying appropriate forecasting and stock control methods to theoretically generated compound poisson demand data we show that correlation in intermittent demand does play a role in forecast quality and stock control performance negative autocorrelation levels lead to higher service levels than positive values while cost does not significantly change our results also show that high intermittency levels intensify these changes in service level we also show that cross correlation produces results in the opposite direction of autocorrelation in size or intervals that is positive negative cross correlation leads to higher lower service levels

college entry by blacks since 1970 the role of college costs family background and the returns to education college enrollment of black 18 19 year old high school graduates declined from 1980 through 1984 and then rebounded after 1984 this paper presents data from a time series of cross sections of 18 19 year old youths from 1973 through 1988 to test the role of family background direct college costs local economic conditions and returns to college in driving these trends the evidence suggests that on the one hand increases in direct college costs were driving enrollment rates downward throughout the eighties on the other hand dramatic increases in average parental education for black youths exerted upward pressure on college enrollment by blacks particularly in the latter half of the decade the net effect of these two factors contributed to the pattern of decline and recovery observed during the eighties

the diffusion of computers and the distribution of wages abstract when the costs are decreasing workers adopt technology at the point where the costs equal the increased productivity output per worker increases immediately while productivity benefits increase only gradually if costs continue to fall as a result workers in computer adopting labor market groups experience an immediate fall in wages due to increased supply on the other hand adopting workers experience wage increases with some delay this model explains why increased computer use does not immediately lead to higher wage inequality more specifically the results of the model are shown to be consistent with the question why within group wage inequality among skilled workers as a result of computer technology adoption in the united states increased in the 1970s while between group wage inequality and within group wage inequality among the unskilled did not start to increase until the 1980s the model also predicts that the more compressed german wage structure leads to a lagged diffusion of computer technology along with smaller changes in wage inequality our empirical analysis suggests that this is consistent with the actual developments in germany since the 1980s finally the theoretical predictions seem to be of the right magnitude to explain the empirical quantities observed in the data

technical progress and early retirement this paper claims that technical progress induces early retirement of older workers it presents a model where human capital is technology specific so that technical progress erodes some existing human capital this affects mostly older workers who have a smaller incentive to learn the new technology since their career horizon is shorter hence they tend to work less we find support to this erosion effect in hrs data which shows that retirement and unemployment of older workers are positively related to technical progress in their sectors unlike the effect across sectors the model is ambiguous about the aggregate effect of technical progress on labor supply of older workers while in sectors with many innovations it falls due to the erosion effect in other sectors it increases due to higher wages to examine which effect dominates we run a time series test using us data and find that the rate of average technical progress reduces aggregate labor force participation by the old namely the erosion effect dominates

government spending composition technical change and wage inequality in this paper we argue that government spending played a significant role in stimulating the wave of innovation that hit the u s economy in the late 1970s and in the 1980s as well as the simultaneous increase in inequality and in education attainments since the late 1970s u s policymakers began targeting commercial innovations more directly and explicitly we focus on the shift in the composition of public demand toward high tech goods which by increasing the market size of innovative firms functions as a de facto innovation policy tool we build a quality ladders non scale growth model with heterogeneous industries and endogenous supply of skills and show that an increase in the technological content of public spending stimulates r d raises the wage of skilled workers and at the same time stimulates human capital accumulation a calibrated version of the model suggests that government policy explains between 12 and 15 of the observed increase in wage inequality in the period 1976 1991 jel e62 j31 o33 o41

the geography of inequality difference and determinants of wage and income inequality across us metros florida r and mellander c the geography of inequality difference and determinants of wage and income inequality across us metros regional studies this paper examines the geographic variation in wage inequality and income inequality across us metros the findings indicate that the two are quite different wage inequality is closely associated with skills human capital technology and metro size in line with the literature but these factors are only weakly associated with income inequality furthermore wage inequality explains only 15 of income inequality across metros income inequality is more closely associated with unionization race and poverty no relationship is found between income inequality and average incomes and only a modest relationship between it and the percentage of high income households