dynamic expected shortfall a spectral decomposition of tail risk across time horizons abstract the tail risk of financial institutions is traditionally measured by expected shortfall es that does not characterize risk changes over investment horizons using wavelet analysis we propose a new method to capture the dynamics of es across time horizons the new method decomposes the stock return of financial institutions into different frequency e g short mid and long run components and then models the dynamics of these components separately to produce an aggregated es forecast we provide numerical and empirical examples to illustrate the new method we also study the relevance of each frequency component to out of sample es forecasts over different predictive horizons our empirical results confirm that the different frequency components of stock returns exhibit different persistence explicitly considering this distinction when modeling es significantly improves the out of sample forecasting performance in addition excluding the long run e g yearly return component can largely reduce short run e g weekly or monthly es forecasts without impacting the regulatory quality of the risk assessment

new firm startups technology and macroeconomic fluctuations new firm startup activity is examined within a framework pooling a cross section of 117 industries over six time periods between 1976 and 1986 a model is introduced relating startup activity both to elements of the business cycle in particular the macroeconomic growth rate the cost of capital and the unemployment rate and to industry specific characteristics especially the technological conditions underlying the industry the pooled cross section regression results suggest that macroeconomic fluctuations as well as industry specific elements contribute to startup activity while new firm startups respond positively to macroeconomic growth they are promoted by a low cost of capital and high unemployment rate a somewhat surprising result is that new firm startups are not apparently deterred in capital intensive industries and where r d expenditures play an important role the empirical results suggest that new firms may be able to overcome their inherent size and experience disadvantages in such markets through exploiting university research and pursuing innovative activity

comparisons between small business data base useem and bureau of labor statistics bls employment data 1978 1986 the bls versus useem comparison generally points out some major classification differences in the data sets particularly in the classification and growth of larger establishments useem and bls data generally agree as to the direction of employment growth over the 1978 to 1986 period differences occur in 7 of the 63 comparisons of employment growth but bls attributes a greater proportion of growth to larger reporting units useem to smaller establishments bls and useem data have concurring positive or negative growth rates for all size classes in the construction wholesale trade services and finance insurance and real estate industries

rates of time preference and valuations of the duration of life abstract this paper develops a multi period markov model of the lifetime choice of occupational fatality risks the empirical model analyzes the wage effects of job risks using the 1982 university of michigan panel study of income dynamics in conjunction with death statistics from the u s national traumatic occupational fatality survey evidence regarding workers intertemporal choices with respect to risks with long term implications is broadly consistent with rational behavior workers implicit real rate of time preference with respect to future life years equals approximately 11 percent this rate of time preference decreases with education

reconciling sustainability and discounting in cost benefit analysis a methodological proposal abstract the incorporation of the intergenerational equity objective has rendered the traditional cost benefit analysis cba approach obsolete for the evaluation of projects presenting an important number of environmental externalities and for those whose impacts extend throughout a long period of time based on the assumption that applying a discount rate rewards current consumption and therefore that it is only possible to introduce a certain intergenerational equity in a cost benefit analysis in this work we propose an approach to discounting based on a different rationale for tangible and intangible effects we designed two indicators of environmental profitability a the intergenerational transfer amount ita which quantifies in monetary units what the current generation is willing to pass on future generations when an environmental restoration project is carried out and b the critical environmental rate cer measures the implicit environmental profitability these concepts were tested through an empirical case study pertaining to the assessment of an erosion control project in the southeast of spain the results yield traditional profitability indicators that are higher and probably closer to the real values set by the contemporary society the information provided by the environmental profitability indicators proposed renders more transparency to the quantification of the levels of intergenerational equity applied thereby facilitating the difficult reconciliation of the cba technique with the objective of sustainability

evaluating interval forecasts a complete theory for evaluating interval forecasts has not been worked out to date most of the literature implicitly assumes homoskedastic errors even when this is clearly violated and proceed by merely testing for correct unconditional coverage consequently i set out to build a consistent framework for conditional interval forecast evaluation which is crucial when higher order moment dynamics are present the new methodology is demonstrated in an application to the exchange rate forecasting procedures advocated in risk management

forecasting portfolio value at risk with nonparametric lower tail dependence estimates abstract we propose to forecast the value at risk of bivariate portfolios using copulas which are calibrated on the basis of nonparametric sample estimates of the coefficient of lower tail dependence we compare our proposed method to a conventional copula garch model where the parameter of a clayton copula is estimated via canonical maximum likelihood the superiority of our proposed model is exemplified by analyzing a data sample of nine different bivariate and one nine dimensional financial portfolio a comparison of the out of sample forecasting accuracy of both models confirms that our model yields economically significantly better value at risk forecasts than the competing parametric calibration strategy

statistical models of consumer behavior with heterogeneous values and constraints in a market with heterogeneous individuals the fact that a particular group of individuals are the consumers of a particular product already indicates that there exist systematic differences between them and the average person simple tools from statistical theory are used here to analyze the implications of consumer diversity it is argued that an increase in consumer diversity will increase the gains from trade and that there is a shadow price of heterogeneity associated with product quality throughout the discussion the significance of consumer self selection and the distinction between average and marginal will be emphasized

road transport externalities during the last decade much progress has been made in defining measuring the external costs of transport as the cost of tolling equipment falls the set of realistic policy options to internalise these externalities will continue to grow this will determine the research and policy agenda we make three points firstly empirical work is still necessary to better identify marginal external costs including congestion accident and environmental costs secondly any assessment of policy options should treat externalities simultaneously the use of pricing instruments and emissions standards are discussed within this framework thirdly we emphasise the role of government designing the optimal road pricing institutions requires consideration of horizontal and vertical tax competition while double dividend arguments are central to the question of securing public support

accounting for net entry into greek manufacturing by establishments of varying size adopting the view that size matters in understanding entry exit patterns this research explores the nature and causes of net entry patterns of various size defined groups of establishments in the case of a less industrialised country greece the hypothesis to be tested is that the determinants of entry are not independent of firm size throughout this paper the analysis has had to confront difficulties arising from the use of net entry rates defined at the size class level the degree of size disaggregation used in this paper is considerably finer than used before five employment defined size classes have been used instead of sliding cut off points discriminating between small and large firms unlike other research using pooled models to explain variation in entry exit rates across industries the data used here are characterised by the absence of significant industry specific systematic variation overall the results obtained in this paper indicate that there is a gradation in the responses of different size classes to stimuli defined at the industry level evidence is offered that small firms are different in that they manage to overcome entry barriers perhaps adopting different survival strategies and that large firms are well aware of market conditions and are in an advantageous position to overcome many of the problems imposed by entry barriers size classes in the middle of the size class distribution offer a rather mixed result due to size related advantages and disadvantages

net entry of firms into greek manufacturing the effects of business conditions this research explores the nature and causes of net entry into manufacturing industry in greece previous work has rarely considered these issues in the context of small but open and not particularly industrialised economies the exact nature of the focus of interest net entry is discussed first illustrating that this is a complex variable to account for although arguably still interesting and useful net entry needs to be considered as variable worthy of study in its own right as it reflects an outcome of processes of gross entry and exit certainly it need not be interpreted only as entry as is often the case next comes the question of the degree of variation both temporally and sectorally that net entry exhibits in the context of contemporary greek manufacturing some temporal variation in net entry rates is demonstrated and there follows a discussion of how such variation might be explained potentially in theory the empirical testing of these hypotheses point to findings that are different to those discovered in different contexts for greek manufacturing profitable business opportunities were not shown to be a sufficient condition of higher net entry but the cost advantages of large scale operations did both encourage entry and discourage exit the cost of capital and the overall condition of the economy were negatively related to net entry however the role of industry growth import penetration and export orientation tend to confirm findings in other studies

modeling long memory and structural breaks in conditional variances an adaptive figarch approach this paper introduces a new long memory volatility process denoted by adaptive figarch or a figarch which is designed to account for both long memory and structural change in the conditional variance process structural change is modeled by allowing the intercept to follow a slowly varying function speci ed by gallant 1984 s exible functional form a monte carlo study nds that the a figarch model outperforms the standard figarch model when structural change is present and performs at least as well in the absence of structural instability an empirical application to stock market volatility is also included to illustrate the usefulness of the technique

public vs private demand for covering long term care expenditures this article studies the determinants of the willingness to pay wtp for long term care ltc insurance coverage two alternatives are considered one compulsory financed through taxes the other purchased on a voluntary basis and paid through a premium wtp was elicited through open ended contingent valuation within a survey conducted in the italian region emilia romagna about ltc population needs we model information on individual wtp as a two stage process where respondents first establish their interest for ltc cover then state their wtp results show that interest and wtp are influenced by different variables and that differences arise also between the wtp for public and private coverage

a model of the demand for longevity and the value of life extension we specify a demand function for longevity or quantity of life along with corresponding demand functions for indicators of quality of life and a value of health and life extension function we show that the demand for health must be derived in conjunction with that for longevity and the related consumption plan and that all choices depend on initial individual endowments and terminal conditions our comparative dynamics predictions indicate that optimal health and longevity are increasing functions of endowed wealth rather than necessarily current income that improvements in opportunities to produce health can accentuate the differences between endowed health and attained longevity levels and that the value individuals ascribe to their health may be increasing over a good portion of their life cycle we use this model to analyze observed empirical variations in levels and trends of life expectancy and in exposure to health risks across different population groups

crude oil risk forecasting new evidence from multiscale analysis approach fluctuations in the crude oil price allied to risk have increased significantly over the last decade frequently varying at different risk levels although existing models partially predict such variations so far they have been unable to predict oil prices accurately in this highly volatile market the development of an effective predictive model has therefore become a prime objective of research in this field our approach albeit based in part on previous research develops an original methodology in that we have created a risk forecasting model with the ability to predict oil price fluctuations caused by changes in both fundamental and transient risk factors we achieve this by disintegrating the multi scale risk structure of the crude oil market using variational mode decomposition normal and transient risk factors are then extracted from the crude oil price using variational mode decomposition and modelled separately using the quantile regression neural network qrnn model both risk factors are integrated and ensembled to produce the risk estimates we then apply our proposed risk forecasting model to predicting future downside risk level in three major crude oil markets namely the west taxes intermediate wti the brent market and the opec market the results demonstrate that our model has the ability to capture downside risk estimates with significantly improved precision thus reducing estimation errors and increasing forecasting reliability

the relationship between firm growth size and age estimates for 100 manufacturing industries this study uses a sample of all firms operating in 100 manufacturing industries to examine some aspects of firm dynamics it finds that firm growth the variability of firm growth and the probability that a firm will fail decrease with firm age it also finds that firm growth decreases at a diminishing rate with firm size even after controlling for the exit of slow growing firms from the sample gibrat s law therefore fails although the severity of the failure decreases with firm size copyright 1987 by blackwell publishing ltd

caviar conditional autoregressive value at risk by regression quantiles value at risk var has become the standard measure of market risk employed by financial institutions for both internal and regulatory purposes var is defined as the value that a portfolio will lose with a given probability over a certain time horizon usually one or ten days despite its conceptual simplicity its measurement is a very challenging statistical problem and none of the methodologies developed so far give satisfactory solutions interpreting the var as the quantile of future portfolio values conditional on current information we propose a new approach to quantile estimation which does not require any of the extreme assumptions invoked by existing methodologies such as normality or i i d returns the conditional autoregressive value at risk or caviar model moves the focus of attention from the distribution of returns directly to the behavior of the quantile we specify the evolution of the quantile over time using a special type of autoregressive process and use the regression quantile framework introduced by koenker and bassett to determine the unknown parameters since the objective function is not differentiable we use a differential evolutionary genetic algorithm for the numerical optimization utilizing the criterion that each period the probability of exceeding the var must be independent of all the past information we introduce a new test of model adequacy the dynamic quantile test applications to simulated and real data provide empirical support to this methodology and illustrate the ability of these algorithms to adapt to new risk environments

technology and the dynamics of industrial structures an empirical mapping of dutch manufacturing this paper explores the empirical link between on the one hand innovation and on the other hand industrial structure and dynamics in the netherlands we use the concept of technological regimes as the guiding framework to interpret this relationship the data are drawn from the production statistics and the business register of manufacturing firms in the netherlands and the second community innovation survey a classification of technological regimes that refines pavitt s taxonomy is applied to the data our analysis is aimed at identifying the variables that are best able to discriminate between technological regimes for our dutch case we find that a mix of innovation related and market structure related variables account for most variability and broad differences across regimes dynamic market structure variables account for an additional share of variability and finer differences across regimes overall we conclude that the concept of technological regimes provides a useful framework that helps to shed further light on the relationship between innovation and market structure

universal health insurance in the clinton plan coverage as a tax financed public good the financing arrangements embodied in the clinton health reform plan involve some important differences in the way in which public goods are usually financed the subsidies to small low wage firms mandated to provide benefits distort markets in both labor and products and offer incentives for the creation of small firms in addition the financing scheme implicitly envisions a head tax on families at modest income levels but offers a possible rationale for it nevertheless the main reason for many of the financing features appears to be an attempt to hold down the apparent budgetary cost of universal coverage

improving daily value at risk forecasts the relevance of short run volatility for regulatory quality assessment abstract in this paper we present a novel perspective on data filtering and present an innovative wavelet based approach that leads to improved value at risk var forecasts a separation of financial conditional volatility into short mid and long run components allows us to study the relevance of these frequency components with respect to a regulatory quality assessment for daily var forecasts a simulation study and an analysis of daily market prices suggest that short and mid run information components cover the relevant information that is necessary for estimating adequate daily var excluding long run information components reduces daily var forecasts by up to 4 and does not impact the quality of regulatory back testing

potential entrepreneurship in japan the aim of this paper is to investigate the potential for entrepreneurship in japan using the employment status survey which is the only government administered survey that includes questions about the desire to become an entrepreneur we find that there are still a number of potential entrepreneurs in japan despite a recent decline in the number of new firms being established we also find that there is a large regional variation in the distribution of entrepreneurial potential with clustering into a few regions and the level in tokyo being exceptional further using panel data on 47 prefectures from 1982 to 1997 we examine the determinants of entrepreneurial potential the estimation results show that the price cost margin market size market growth and the unemployment rate have positive effects on the potential for entrepreneurship

the wandering weekday effect in major stock markets this paper reports a wandering weekday effect the pattern of day seasonality in stock market returns is not fixed as assumed in the monday or weekend effects but changes over time analysing daily closing prices in eleven major stock markets during 1993 2007 our results show that the wandering weekday is not conditional on average returns in the previous week the twist in the monday effect nor does it diminish through the period of analysis the results have important implications for market efficiency and help to reconcile mixed findings in previous studies including the reported disappearance of the weekday effect in recent years

a theory of time preference grant a taylor this article proposes that people generally prefer present consumption to future consumption because their expected utility from consumption eventually falls as their mental and physical abilities eventually decline with age moreover contrary to the ubiquitous intertemporal formulation with a constant rate of time preference and contrary to three recent theories of time preference that predict decreasing discounting as people age this article asserts that discounting increases over the life cycle this hypothesis is supported by data from the panel study of income dynamics as well as evidence from numerous previous studies jel d91 1 introduction despite the almost universal assumption of time preference in models of intertemporal choice an adequate explanation of why people discount the future has not been provided 1 olsen and bailey 1981 make a convincing case for positive time preference by contradiction i e without time preference models of intertemporal choice do not yield predictions consistent with observed behavior but they do not explain why individuals would rationally discount the future 2 three recent studies have attempted to provide the explanation rogers 1994 argues that societies that discount the future at a rate of about 2 will be the long run survivors in an evolutionary fitness situation 3 posner 1995 argues that discounting occurs because individuals have multiple selves that is people are weighting their present consumption far more heavily than their future consumption because the present self and the future self are in some meaningful sense separate persons 92 becker and mulligan 1997 argue that discounting occurs because of a rational defective recognition of future utilities 730 but as will be shown these three theories are inconsistent with empirical evidence on consumption over the life cycle in at least one important aspect this article constructs and empirically supports a new theory of time preference the hypothesis is that people do not have an intrinsic preference for present consumption relative to future consumption instead the instantaneous utility function also known as the felicity function is expected to vary with age just as people s physical and mental abilities vary with age in other words the ability to enjoy consumption eventually deteriorates over the life cycle along with other abilities this life cycle view of the expected utility function causes people to rationally devalue consumption in periods of low expected felicity that is discount future consumption perhaps this is what is meant by the cliche don t wait until you are too old to enjoy it moreover this causes individuals implicit discount rates to vary systematically with age 4 in fact this provides the testable implication of the theory the standard specification of intertemporal preferences holds the discount rate constant over th e life cycle 5 to be more precise in the early stage of the life cycle the capacity to enjoy consumption may be expected to rise hence a young individual s discount rate may be negative figure 1 illustrates this possibility with a hypothetical adult life cycle marginal felicity function for a given level of consumption u sub c c a c denotes consumption and a denotes age and its corresponding discount rate function rho a the vast majority of wealth is held by older people that is those in the declining stage of their abilities thus the preference for present consumption over future consumption appears to hold in the aggregate this view of intertemporal preferences may at first seem inconsistent with practically all dynamic analyses which are based on the notion of stationary utility on further consideration however the hypothesis is quite consistent with modern consumer theory since becker 1965 it has been widely accepted that households derive utility from commodities that are produced with market goods combined with household time and skills i

a closer look at the effect of market growth on industries profits everybody talks about the relation of industries profit rates to their markets rates of growth but nobody does anything about it specifically researchers have confirmed the effect of the growth of nominal output on profits in many multivariate studies without specifying closely the hypothesis under test or the measure of demand growth appropriate to test it a profits growth relationship could stem from several mechanisms the lagged adaptation of capacity to unexpected changes in demand reactions of oligopolists to disturbances in their consensus etc these mechanisms how and where they work hold their own normative interest therefore knowing what behavior and what structure lying behind it accounts for the profits growth relationship should do more than improve the specifications of our studies of allocative efficiency it should also expand our knowledge of adaptive processes that are important and hard to observe directly in this paper we shall synthesize the available explanations of why changes in market demand should affect an industry s profits then present a statistical test of the relative significance of the competing explanations

entry and exit on the competitive fringe microeconomic theories of industry evolution reserve key roles for the entry and exit of firms competitive models of industry supply often assume that individual firms have ushaped long run average cost curves in consequence an industry s output adjustment in movement from one long run equilibrium to another is entirely accomplished through the entry and exit of firms rather than through changes in long run equilibrium output of individual firms in empirical applications the speed of movement to new equilibrium levels of output and price measured by the time it takes for profits to return to competitive levels following a demand shock clearly depends upon the ease of entry and exit however the simplest competitive models have a clear theoretical weakness abundant evidence against u shaped long run average cost curves precludes a simple identification of entry with industry expansion and exit with industry contraction expansion of industry supply can be met either by incumbents or entrants and we have little empirical evidence of the division entry conditions are also a staple of oligopoly and monopoly models potential entry constrains the pricing options open to industry leaders and actual entry of new firms and new products erodes at varying rates the market power of incumbent firms if actual entry responds rapidly to profit opportunities then the persistent exercise of monopoly power will be rare however analyses of monopoly and oligopoly models typically approach entry indirectly by inferring that persistent profit differentials reflect high barriers to entry there are few direct tests of the effects of such barriers on actual entry despite their importance very few empirical studies of entry and exit exist severe data limitations restrict both the number of studies and the scope of extant analyses the research reported in this paper provides measures of entry and exit in 46 food manufacturing industries during the 1976 82 period measures of incidence the number of firms as well as extent the size of firms are provided the analysis also distinguishes between diversified firms and specialist producers entry and exit rates vary considerably across industries and the paper reports the results of statistical analyses that account for industry differences in entry and exit rates by specialist firms

quality of life and the wtp for an increased life expectancy at an advanced age abstract in this study we report an attempt to measure the value adult swedes impute to an increased survival probability at high ages a rating scale between the worst possible quality of life 1 and the best possible quality of life 10 is used to indicate the quality of life a person expects to achieve at an advanced age we find a highly significant correlation between this quality measure and the insurance premium a person is willing to pay in exchange for a programme increasing the expected length of life by one year conditional on having survived until the age of 75 years the maximum insurance premium the average person is willing to pay for such a programme is less than 1500 the willingness to pay increase with a person s age but at a low rate the implied average marginal rate of time preference is about 1 percent

sentiment and stock returns the sad anomaly revisited notice this is the author s version of a work that was accepted for publication in journal of banking finance changes resulting from the publishing process such as peer review editing corrections structural formatting and other quality control mechanisms may not be reflected in this document changes may have been made to this work since it was submitted for publication a definitive version was subsequently published in journal of banking finance vol 34 issue 6 june 2010 doi 10 1016 j jbankfin 2009 11 027

typology of the french regional development revealing the refugee versus schumpeter effects in new firm start ups in this article we analyse the relationships between unemployment rates and new firm start up rates in france using a quarterly data basis covering the period 1993 to 2011 we identify thanks to data analysis methods different classes that show different types of development among the french regions for each of these classes the existence of refugee schumpeter effects both in the short run and in the long run is revealed at the national level it appears that the refugee effect explains the dynamics of entrepreneurship in france over the period 2000 to 2011 necessity is the key motivation for new french firms

a guide to wavelets for economists abstract wavelet analysis although used extensively in disciplines such as signal processing engineering medical sciences physics and astronomy has not fully entered the economics discipline yet in this survey article wavelet analysis is introduced in an intuitive manner and the existing economics and finance literature that utilizes wavelets is surveyed and explored extensive examples of exploratory wavelet analysis are given most using canadian us and finnish industrial production data finally potential and possible future applications for wavelet analysis in economics are discussed

determinants of firm start up size an application of quantile regression for ireland in this paper we provide empirical evidence on the determinants of firm start up size using data for the manufacturing sector in ireland and compare our results with recent findings for portuguese manufacturing industries mata and machado 1996 to allow for firm heterogeneity between firm entrants we use quantile regression techniques for our empirical estimation we find that the determinants of start up size differ in their importance for small and large scale entrants in particular industry size and industry growth seem to affect large scale entrants only

small firm entry in us manufacturing a cross section empirical analysis examining the entry behavior of small firms is provided in this paper while the authors find that certain traditional market structure characteristics and entry barriers have a strong impact on small firm entry behavior the reliance upon innovative strategy by small firms also explains a significant amount of the variation in the pattern of entry by small firms they conclude that small firm entry is at least partially determined by entry barriers industry specific characteristics facilitating retaliatory conduct by incumbent firms and the reliance upon innovative strategy by small firms copyright 1989 by the london school of economics and political science

animal spirits technology shocks and the business cycle the last few years have witnessed a revival of business cycle models in which beliefs of agents have played a leading role in explaining economic fluctuations 1 most of these models involve strong economy wide increasing returns to scale in order for sunspot equilibria to exist in a recent paper however basu and fernald 1996 present evidence that returns to scale are far from evenly distributed across the u s economy in particular they report that scale economies are present mainly in the domain of durable goods production in the nondurable goods sector of the u s economy evidence of increasing returns to scale cannot be found

improving the value at risk forecasts theory and evidence from the financial crisis abstract the recent financial crisis has raised numerous questions about the accuracy of value at risk var as a tool to quantify extreme losses in this paper we develop data driven var approaches that are based on the principle of optimal combination and that provide robust and precise var forecasts for periods when they are needed most such as the recent financial crisis within a comprehensive comparative study we provide the latest piece of empirical evidence on the performance of a wide range of standard var approaches and highlight the overall outperformance of the newly developed methods

the effect of risk context on the value of a statistical life a bayesian meta model this paper presents the first value of statistical life vsl meta analysis that empirically estimates correction factors for out of context benefits transfer bt purposes in the field of mortality risk reductions elicited willingness to pay values in one risk context say road safety are frequently applied in other risk contexts like air pollution however differences in risk perception and the population at risk across contexts are likely to result in diverging vsl estimates in a meta analysis of 26 international stated preference studies a bayesian model is estimated regressing contingent values for mortality risk reductions originating from three different risk contexts on the characteristics of the risk reduction itself and additional variables characterizing the underlying studies a willingness to pay wtp premium for mortality risk reductions in the air pollution and general mortality risk context relative to improving road safety is observed evaluated at the mean road safety vsl estimates should be multiplied by a factor 1 8 before being applicable in the air pollution context moreover in an illustrative bt exercise we find limited overlap in the set of context specific predictive vsl distributions consequently out of context bt results in a substantial over or underestimation of the vsl

technological regimes and sources of entrepreneurship this paper concerns the technological determinants of entrepreneurial behaviour by applying a typology of technological regimes which describes the nature of the technological environment in which firms operate this paper examines the sources and obstacles to entrepreneurial entry related to the process of technical change two major points are suggested first innovation in technologies of high or increasing opportunities is not always associated with entrepreneurial behaviour but can enhance the competitive advantage of existing firms second opportunities for entrepreneurship are shaped by the nature of knowledge underlying different technologies these points are illustrated using u s patent statistics classified by technical field and sector of firm s principal product activity different combinations of sources of technological entry barriers and technological opportunity are identified in science based technologies chemical technologies core technologies in complex systems product engineering technologies and process engineering technologies this paper argues that such a characterisation of the dynamics of knowledge accumulation is important for interpreting the variety of dynamics of industrial competition

valuing environmental health effects an economic perspective this paper provides an overview of some of the issues involved in comparing benefit cost analysis and cost effectiveness analysis based on quality adjusted life years as alternative approaches to assessing environmental policies that affect human health it concludes that i although qalys have the advantage of reflecting policy impacts on both health status and longevity in a single scalar measure they are not consistent with utility theory unless individuals preferences satisfy some restrictive conditions ii they do not capture other important aspects of the valuation of changes in mortality and morbidity iii cost effectiveness analysis based on qalys as a measure of effectiveness omits non health related effects of environmental policy and iv it leaves unanswered the important question of what level of environmental regulation is appropriate