the physical dimension of international trade part 1 direct global flows between 1962 and 2005 abstract the physical dimension of international trade is attaining increased importance this article describes a method to calculate complete physical trade flows for all countries which report their trade to the un the method is based on the un comtrade database and it was used to calculate world wide physical trade flows for all reporting countries in nine selected years between 1962 and 2005 the results show increasing global trade with global direct material trade flows reaching about 10 billion tonnes in 2005 corresponding to a physical trade volume of about 20 billion tonnes adding both total imports and total exports the share from european countries is declining mainly in favour of asian countries the dominant traded commodity in physical units was fossil fuels mainly oil physical trade balances were used to identify the dominant resource suppliers and demanders australia was the principal resource supplier over the period with a diverse material export structure it was followed by mainly oil exporting countries with varying volumes as regards to regions latin america south east asian islands and central asia were big resource exporters mostly with increasing absolute amounts of net exports the largest net importers were japan the united states and single european countries emerging countries like the asian tigers with major industrial productive sectors are growing net importers some of them to an even higher degree than european countries altogether with the major exception of australia and canada industrialized countries are net importers and developing countries and transition countries are net exporters but there are important differences within these groups

modeling purchasing behavior with sudden death a flexible customer lifetime model this study proposes a new customer lifetime model the gamma gompertz distribution g g the advantage of this model relative to the well known pareto distribution is twofold i its probability density function can exhibit a mode at zero or an interior mode and ii it can be skewed to the right or to the left we combine the g g with a negative binomial distribution nbd and obtain the moments of the distribution of the number of transactions over 0 t and t t t out of six data sets the g g nbd model provides a notable improvement in the log likelihood over the pareto nbd model in four data sets it can indicate substantial differences in expected residual lifetimes compared to the pareto nbd and induce a retention rather than acquisition policy on the average the g g nbd exhibits slightly better forecasts of the mean number of transactions than the pareto nbd this paper was accepted by pradeep chintagunta marketing

relating life cycle assessment indicators to gross value added for dutch dairy farms sustainable dairy production requires farms that are economically viable environmentally sound and socially acceptable a low environmental impact of milk production is not necessarily associated with an economically viable farm to gain insight into a possible trade off between economic and environmental sustainability the relation between the environmental and economic indicators of dairy farms was quantified and farm characteristics that influence this relation were identified economic and environmental indicators were quantified for 119 specialized dairy farms in 2005 based on data from the dutch farm accountancy data network fadn economic indicators used were gross value added expressed per kg fat and protein corrected milk fpcm or expressed per unit of labour i e labour productivity environmental indicators used were land use per kg fpcm energy use per kg fpcm global warming potential per kg fpcm eutrophication and acidification potential per kg fpcm or per ha of land environmental indicators were deduced from a life cycle assessment high labour productivity on dairy farms was associated with low on farm energy use total and on farm land use total and on farm global warming potential and total and off farm acidification potential per kg fpcm high labour productivity however was associated also with high on farm eutrophication and acidification potential per hectare from partial least squares regression analysis it was concluded that relations between economic and environmental indicators were affected mainly by milk production per ha annual milk production per cow farm size and amount of concentrates per kg fpcm an increase in annual milk production per cow for example not only increased labour productivity reduced energy use and global warming potential per kg fpcm but also in the case of an unchanged stocking density increased eutrophication and acidification per ha to be economically and environmentally sustainable animal production in the netherlands therefore should focus on high animal productivity i e high annual milk production per cow and efficient use of feed per kg milk and moderate stocking density provided that a good animal welfare standard is guaranteed

the unequal exchange of dutch cheese and kenyan roses introducing and testing an lca based methodology for estimating ecologically unequal exchange the theory of ecologically unequal exchange eue posits that international trade is structurally organized in a manner that allows a net transfer of resources from peripheral developing to core industrialized countries the consequence it is argued is under development in the periphery and augmented productive capacity in the core eue thus challenges the neoliberal free market argument that exchange at market prices is symmetric and fair an lca based methodology for estimating eue that holds constant the variable market price is introduced and tested on contemporary trade of dutch cheese and kenyan coffee and roses specifically the exchange of embodied land water energy global warming potential and labor is assessed the results confirm the theory s hypothesis at a fixed market price more embodied kenyan resources are exchanged for less dutch resources however kenyan roses give different results from coffee eue between countries can only be conclusively determined by considering the total biophysical trade balance but by calculating quantities of embodied resources per unit of exchange value it is possible to detect unequal exchange even at the level of individual commodities while integration of biophysical metrics alongside monetary valuation is recommended ultimately rethinking the structure policies and politics of international trade is necessary

note extending the rotterdam model to test hierarchical market structures two issues that have implications across a firm s marketing activities are the estimation of the market response functions and the determination of the structure of the market in which its products compete in a recent paper clements and selvanathan clements k w e a selvanathan 1988 the rotterdam demand model and its application to marketing marketing sci 7winter 60 75 describe how the rotterdam demand system can be used to study these two issues in a joint framework in this note we extend their model to test hierarchical market structures using data at the brand form level we also incorporate idiosyncratic response coefficients that capture the effects of advertising and or other nonprice marketing mix variables separate from the effects of a price change these extensions provide additional insights into the nature and extent of competition among brands within a product class

human appropriation of natural capital a comparison of ecological footprint and water footprint analysis the water footprint concept introduced in 2002 is an analogue of the ecological footprint concept originating from the 1990s whereas the ecological footprint ef denotes the bioproductive area hectares needed to sustain a population the water footprint wf represents the freshwater volume cubic metres per year required in elaborating the wf concept into a well defined quantifiable indicator a number of methodological issues have been addressed with many similarities to the methodological concerns in ef analysis the methodology followed in wf studies is in most cases analogous to the methodology taken in ef studies but deviates at some points well reasoned it has been chosen for instance to specifically take into account the source and production circumstances of products and assess the actual water use involved thus not taking global averages as a result one can exactly localise the spatial distribution of a water footprint of a country with respect to the outcome of the footprint estimates one can see both similarities and striking differences food consumption for instance contributes significantly to both the ef and the wf but mobility and associated energy use is very important only for the ef from a sustainability perspective the wf of a country tells another story and thus at times will put particular development strategies in a different perspective the paper reviews and compares the methodologies in ef and wf studies compares nation s footprint estimates and suggests how the two concepts can be interpreted in relation to one another the key conclusion is that the two concepts are to be regarded as complementary in the sustainability debate

on the life cycle metaphor where ecology and economics diverge abstract there is an attractive analogy between nature and industry based on the similarity of natural functions and certain industrial activities for instance animals ingest eat and digest food finally there are metabolic wastes firms are analogous to organisms in several respects insofar as they consume material resources process digest them and produce output products and excrete wastes firms like organisms also compete with each other for resources curiously enough one of the apparent differences between natural and man made systems is actually not one like the industrial system the natural system does not recycle everything however there are at least four real and important differences between the biosphere ecology and the technosphere economy first there is no primary producer in the economic system analogous to what photosynthesizers play in the biosphere inputs to the economy are mostly natural resources capital services and labor second in the economic system output is a heterogeneous mix of manufactured products and services labor in economics is an input but not an output the economic system recycles much less than the ecological system but utilizes a far greater suite of elements in the biosphere there are no products as such growth is tantamount to accumulation of embodied solar exergy in the form of cellulose sugars lipids and proteins the biosphere produces only wastes and more of itself plus dead matter third in the biosphere there are no markets there is no medium of exchange like money and there is nothing analogous to paid labor exchanges are involuntary i e by predation parasitism or theft fourth evolution in nature is driven by differentiation by random mutations of the genome and darwinian selection based on reproductive success in economics differentiation is based on discovery invention and innovation by intelligent economic agents and selection is based on competition at the individual or firm level either way the economic system is not closely analogous to an ecosystem attempts to use ecological concepts in an economic context are often misleading and unjustified the paper discusses the implications of the eco eco mismatch for resource accounting and life cycle analysis

the importance of modeling temporal dependence of timing and quantity in direct marketing abstract the analysis of customer value in direct marketing typically combines customer timing and quantity data into a single statistic that is used to compute lifetime values rank order customers for differential action and identify prospects for cross selling however current models assume that purchase timing and quantity decisions are independently realized i e uncorrelated over time given individual level parameters in this article the authors show that customer value calculations can be severely biased in these models when timing and quantity are dependently related the authors propose alternative models that lead to substantial gains in profitability in two direct marketing data sets the results indicate that the commonly held assumption of independence leads to an overvaluation of customer value

real effective exchange rate and the constant elasticity of substitution assumption abstract the real effective exchange rate reer is an aggregation of several bilateral real exchange rates assuming constant elasticity of substitution ces between goods from different countries we investigate the validity of the ces assumption by estimating manufacturing export equations for 56 countries over 26 years under the ces assumption splitting the reer into two components should not increase the fit in an export equation and the coefficients on the two reers should be equal we reject both these implications and find that the export equations with two reers vs oecd and vs nonoecd countries perform better than the traditional ones

investigating household purchase timing decisions a conditional hazard function approach the purchase timing decision is an important component of the dynamics of a household s purchase behavior this decision is influenced by marketing and other variables and the modeling of this dependence has recently received attention in the literature in this paper we build on previous studies and develop a comprehensive stochastic model that incorporates the major factors influencing interpurchase times specifically we use a generalized version of cox s proportional hazard model to test among competing probability distributions for the interpurchase times while incorporating effects due to marketing variables observed household characteristics and unobserved heterogeneity across households the empirical finding from analyzing the iri coffee data suggests that the interpurchase times cannot be adequately described by probability distributions such as exponential erlang 2 or weibull the effects of unobserved heterogeneity are significant and they impact the estimates of the effects of the covariates we also find that a nonparametric procedure for estimating the effects of unobserved heterogeneity provides the best overall fit to the data and yields covariate estimates that are more consistent with prior expectations our model is validated by replicating the substantive empirical findings on an additional product category

colombian international trade from a physical perspective towards an ecological prebisch thesis abstract prebisch s approach to economic development was based on the notion that there is an international historical division of labour peripheral countries are specialised in exporting primary goods while centre countries export industrial goods the terms of trade for peripheral countries tend to deteriorate this approach can be extended to ecological issues the international centre periphery division does not only involve the monetary exchange of goods and capital but also the physical exchange in which southern countries provide materials and energy so that northern countries can develop their socioeconomic metabolism this metabolic process is guaranteed through cheap prices for primary goods this paper aims to apply and extend prebisch s thought on unequal exchange both monetary and ecological in relation to colombian trade in the period 1970 2002 using material flow analysis

ticking away the moments timing regularity helps to better predict customer activity accurate predictions of a customer s activity status and future purchase propensities are crucial for managing customer relationships this article extends the recency frequency paradigm of customer base analysis by integrating regularity in interpurchase timing in a modeling framework by definition regularity implies less variation in timing patterns and thus better predictability whereas most stochastic customer behavior models assume a poisson process of random purchase occurrence allowing for regularity in the purchase timings is beneficial in noncontractual settings because it improves inferences about customers latent activity status this especially applies to those valuable customers who were previously very frequently active but have recently exhibited a longer purchase hiatus a newly developed generalization of the well known pareto nbd model accounts for varying degrees of regularity across customers by replacing the nbd component with a mixture of gamma distributions labeled pareto gg

testing competitive market structures an accurate understanding of the structure of competition is important in the formulation of many marketing strategies for example in new product launch product reformulation or positioning decisions the strategist wants to know which of his competitors will be most affected and hence most likely to respond many marketing science models have been proposed to identify market structure in this paper we examine the managerial problem and propose a criterion by which to judge an identified market structure basically our criterion is a quantification of the intuitive managerial criterion that a submarket is a useful conceptualization if it identifies which products are most likely to be affected by our marketing strategies we formalize this criterion within the structure of classical hypothesis testing so that a marketing scientist can use statistical statements to evaluate a market structure identified by 1 behavioral hypotheses 2 managerial intuition or 3 market structure identification algorithms mathematically our criterion is based on probabilities of switching to products in the situation where an individual s most preferred product is not available submarkets are said to exist when consumers are statistically more likely to buy again in that submarket than would be predicted based on an aggregate constant ratio model for example product attributes e g brand form size use situations e g coffee in the morning versus coffee at dinner and user characteristics e g heavy versus light users are specified as hypotheses for testing alternate competitive structures measurement and estimation procedures are described and a convergent approach is illustrated an application of the methodology to the coffee market is presented and managerial implications of six other applications are described briefly

the material basis of the global economy worldwide patterns of natural resource extraction and their implications for sustainable resource use policies abstract material flow accounting and analysis mfa has been established as an influential framework for quantifying the use of natural resources by modern societies so far however no reference data for overall scale and trends of global extraction of natural resources and their distribution between different world regions has been available this paper presents the first comprehensive quantification of the material basis of the global economy i e used domestic extraction in a time series from 1980 to 2002 we analyse time trends for major material groups fossil fuels metals industrial and construction minerals and biomass disaggregated into seven world regions this allows for a an illustration of the global economy s physical growth driven by worldwide processes of economic integration over the past decades and b an indication of the worldwide distribution of environmental pressures associated with material extraction the results show that annual resource consumption of the world economy increased by about one third between 1980 and 2002 this indicates that scale effects due to economic growth more than compensated for other effects such as the relative increase of the service sectors contribution to gdp structural effect and the use of new production technologies with higher material and energy efficiency technology effect the observed growth of natural resource extraction is unevenly distributed over the main material categories with metals showing the highest growth rate the regional analysis shows the increasing importance of asia and latin america in global resource extraction on the global level material intensity i e resource extraction per unit of gdp decreased by about 25 indicating relative decoupling of resource extraction from economic growth the paper concludes with policy recommendations for a more sustainable use of natural resources

external adjustment and the global crisis abstract the period preceding the global financial crisis was characterized by a substantial widening of current account imbalances across the world since the onset of the crisis these imbalances have contracted to a significant extent in this paper we analyze the ongoing process of external adjustment in advanced economies and emerging markets we find that countries whose pre crisis current account balances were in excess of what could be explained by standard economic fundamentals have experienced the largest contractions in their external balance we subsequently examine the contributions of real exchange rates domestic demand and domestic output to the adjustment process allowing for differences across exchange rate regimes and find that external adjustment in deficit countries was achieved primarily through demand compression rather than expenditure switching finally we show that changes in other investment flows were the main channel of financial account adjustment with official external assistance and ecb liquidity cushioning the exit of private capital flows for some countries

estimating the effect of exchange rate changes on total exports this paper shows that real effective exchange rate reer regressions the standard approach for estimating the response of aggregate exports to exchange rate changes imply biased estimates of the underlying elasticities we provide a new aggregate regression specification that is consistent with bilateral trade flows micro founded by the gravity equation

true and spurious duration dependence the identifiability of the proportional hazard model lancaster and nickell 1980 have argued that in the proportional hazard model the effects of time dependence true duration dependence and unobserved sample heterogeneity spurious duration dependence cannot be distinguished we show that both effects can be distinguished if the model allows for observed explanatory variables in the hazard we also discuss the application of our result to practical situations

customer lifetime value measurement the measurement of customer lifetime value is important because it is used as a metric in evaluating decisions in the context of customer relationship management for a firm it is important to form some expectations as to the lifetime value of each customer at the time a customer starts doing business with the firm and at each purchase by the customer in this paper we use a hierarchical bayes approach to estimate the lifetime value of each customer at each purchase occasion by jointly modeling the purchase timing purchase amount and risk of defection from the firm for each customer the data come from a membership based direct marketing company where the times of each customer joining the membership and terminating it are known once these events happen in addition there is an uncertain relationship between customer lifetime and purchase behavior therefore longer customer lifetime does not necessarily imply higher customer lifetime value we compare the performance of our model with other models on a separate validation data set the models compared are the extended nbd pareto model the recency frequency and monetary value model two models nested in our proposed model and a heuristic model that takes the average customer lifetime the average interpurchase time and the average dollar purchase amount observed in our estimation sample and uses them to predict the present value of future customer revenues at each purchase occasion in our hold out sample the results show that our model performs better than all the other models compared both at predicting customer lifetime value and in targeting valuable customers the results also show that longer interpurchase times are associated with larger purchase amounts and a greater risk of leaving the firm both male and female customers seem to have similar interpurchase time intervals and risk of leaving however female customers spend less compared with male customers

trading spaces calculating embodied ecological footprints in international trade using a product land use matrix plum abstract nations import and export biophysical resources with many ecosystems worldwide under mounting stress countries may be increasingly interested in knowing the extent and origin of their ecological imports and dependencies in this paper the ecological footprint is used as a tool to measure the biophysical as opposed to financial value of international trade flows this paper attempts to answer the following question how large of an ecological footprint does a given country exert inside the borders of each of its trading partners records in the un comtrade bilateral trade database are multiplied by a matrix of per product footprint yield coefficients to translate from values in dollars and tonnes to units of hectares the results show that the largest interregional flows are from latin to north america and from north america to asia pacific grouping countries by gdp high and middle income countries appear in footprint terms to trade predominantly with other high and middle income countries and much less with low income countries