Spurious regressions in technical trading

This paper investigates the spurious effect in forecasting asset returns when signals from technical trading rules are used as predictors. Against economic intuition, the simulation result shows that, even if past information has no predictive power, buy or sell signals based on the difference between the short-period and long-period moving averages of past asset prices can be statistically significant when the forecast horizon is relatively long. The theoretical analysis reveals that both ‘momentum’ and ‘contrarian’ strategies can be falsely supported, while the probability of obtaining each result depends on the type of the test statistics employed.     

The Dynamics of Returns to Education in Kenyan and Tanzanian Manufacturing*

We use micro data on manufacturing employees in Kenya and Tanzania to estimate returns to education and investigate the shape of the earnings function in the period 1993–2001. In Kenya, there have been long‐run falls in the returns to education while for Tanzania there is evidence of rising returns in the 1990s. The earnings functions are convex for both countries and this result is robust to endogeneity. Convexity may be part of the explanation as to how rapid expansion of education in Africa has generated so little growth if expansion has been concentrated at lower levels of education.     

Pushing the DEA research envelope

This brief article first investigates key dimensions underlying the progress realized by data envelopment analysis (DEA) methodologies. The resulting perspective is then used to encourage reflection on future paths for the field. Borrowing from the social sciences literature, we distinguish between problematization and gap identification in suggesting strategies to push the DEA research envelope. Emerging evidence of a declining number of influential methodological (theory)-based publications, and a flattening diffusion of applications imply an unfolding maturity of the field. Such findings suggest that focusing on known limitations of DEA, and/or of its applications, while searching for synergistic partnerships with other methodologies, can create new and fertile grounds for research. Possible future directions might thus include ‘DEA in practice’, ‘opening the black-box of production,’ ‘rationalizing inefficiency,’ and ‘the productivity dilemma.’ What we are therefore proposing is a strengthening of the methodology's contribution to fields of endeavor both including, and beyond, those considered in the past.     

High-frequency returns,jumps and the mixture of normals hypothesis

Previous empirical studies find both evidence of jumps in asset prices and that returns standardized by ‘realized volatility’ are approximately standard normal. These findings appear to be contradictory. Using a sample of high-frequency returns for 20 heavily traded US stocks, we show how microstructure noise distorts the standard deviation and kurtosis of returns normalized using realized variance. When returns are standardized using a recently developed realized kernel estimator, the resulting series is clearly platykurtotic and the standard normal distribution is soundly rejected. Moreover, daily returns standardized using realized bipower variation, an estimator for integrated variance that is robust to the presence of jumps, are more consistent with the standard normal distribution. These results suggest that there is no empirical contradiction: jumps should be included in stock price models.     

On the estimation of returns to scale, technical progress and monopolistic markups

A number of theoretical results on estimating returns to scale, technical progress and monopolistic markups are derived when there are multiple outputs and inputs. The choice of value added versus gross output and problems that arise in aggregation across sectors of an economy are also considered. Using US data on manufacturing, evidence is found of increasing returns to scale across all levels of aggregation. Technical progress is typically found to be insignificant implying that economic growth has been driven by increasing returns to scale rather than technical progress. Such findings have important implications for the macroeconomic modeling of economic fluctuations.     

The measurement of pay discrimination between job assignments

The traditional Becker/Arrow model of taste discrimination in pay depicts majority and minority labour as perfectly substitutable, implying that all workers perform precisely the same job assignment and have the same qualifications. The model is thus only appropriate for determining whether ceteris paribus pay differences between white workers and non-white workers, for example, performing job assignment A are attributable to prejudice (‘within-assignment discrimination’). The model is inappropriate for determining whether ceteris paribus pay differences between white workers in assignment A and non-white workers in assignment B reflect prejudice (‘cross-assignment discrimination’). We extend the traditional model to allow for cross-assignment discrimination and we propose an empirical methodology for its estimation. In so doing we address two broad questions: (1) Do predictions about cross-assignment discrimination vary with the form of the production function?; and (2) How can one estimate such discrimination when there is no common measure of productivity? We address the first question by deriving a measure of cross-assignment discrimination for four different production functions—Generalized Leontief, Quadratic, CES, and Cobb-Douglas. The Generalized Leontief provides the most general results, although closed form solutions are not possible. Closed form solutions are obtainable from the other three functions, but only under restrictive assumptions. There are two main findings. First, most predictions are generally robust across functional forms. Second, cross-assignment discrimination depends upon productivity and labour supply differences between the two worker groups, labour market structure, and the interaction between relative group productivity and prejudice. We address the second question by outlining, for future exploration, a two-stage regression methodology in which a standardised (i.e. common) measure of productivity is estimated separately for each occupation. This measure is then incorporated as a right-hand-side explanatory variable in a second-stage, all-occupation regression designed to estimate cross-assignment discrimination. We discuss the proposed methodology with reference to a valuable and interesting test case: The market for professional sports players.     

On the suitability of income inequality measures for regional analysis: Some evidence from simulation analysis and bootstrapping tests

The paper looks at the sensitivity of commonly used income inequality measures to changes in the ranking, size and number of regions into which a country is divided. During the analysis, several test distributions of populations and incomes are compared with a ‘reference’ distribution, characterized by an even distribution of population across regional subdivisions. Random permutation tests are also run to determine whether inequality measures commonly used in regional analysis produce meaningful estimates when applied to regions of different population size. The results show that only the population weighted coefficient of variation (Williamson’s index) and population-weighted Gini coefficient may be considered sufficiently reliable inequality measures, when applied to countries with a small number of regions and with varying population sizes.     

Decompositions of profitability change using cost functions

The paper presents a decomposition of a production unit’s cost ratio over two periods into explanatory factors. The explanatory factors are growth in the unit’s cost efficiency, output growth, changes in input prices and technical progress. In order to implement the decomposition, an estimate of the industry’s best practice cost function for the two periods under consideration is required. Profitability at a period of time is defined as the value of outputs produced by a production unit divided by the corresponding cost. Using the earlier work by Balk and O’Donnell, the paper provides a decomposition of profitability growth over two periods into various explanatory factors that are similar to the cost ratio decomposition except that change in outputs explanatory factor is replaced by two separate factors: an index of output price growth and a measure of returns to scale.     

Wage curve, unemployment duration and compensating differentials

In this study unemployment effects on individual pay are investigated following the study on ‘wage curves’ by Blanchflower and Oswald (1990). In bargaining models, higher unemployment should lower wage pressure; due to compensating wage differential arguments, on the other hand, workers who take jobs with higher layoff risks should be rewarded. In a cross-sectional study on Austrian data, a negative wage curve is confirmed. Contrary to the results by Blanchflower and Oswald no U-shape is found, also long-term unemployment seems to be important. No conclusive evidence of compensating differentials has been determined.     

The motherhood wage gap: What about job amenities?

Women with children tend to earn lower hourly wages than women without children — a shortfall known as the ‘motherhood wage gap’. While many studies provide evidence for this empirical fact and explore several hypotheses about its causes, the impact of motherhood on job dimensions other than wages has scarcely been investigated. In order to assess changes in women's jobs around motherhood, I use data from the German Socio-Economic Panel and employ a first difference analysis. The results reveal that women when having children accommodate at their original employer primarily through adjustments in working hours. Yet, when changing the employer women adjust their jobs in several dimensions, such as different aspects of the work schedule (working hours, work at night or according to a flexible schedule) as well as the level of stress. Further analysis provides some limited support for the motherhood wage gap being explained by adjustments in the work conditions.     

Servitization: Disentangling the impact of service business model innovation on manufacturing firm performance

As manufacturing businesses operate in an ever more competitive, global economy where products are easily commoditized, innovating by adding services to the core product offering has become a popular strategy. Contrary to the economic benefits expected, recent findings pinpoint implementation hurdles that lead to a potential performance decline, the so-called ‘servitization paradox’. In this paper, we analyze this paradox by disentangling the value creation and value appropriation processes of 44 national subsidiaries of a global manufacturing firm turned product-service provider, in the 2001–2007 period. Our findings show that the firm under study is able to successfully transcend the inherent substitution of products by services and to enact complementary sales dynamics between the two activities. Moreover, labor-intensive services such as maintenance, which imply higher levels of customer proximity, further enhance product sales. Empirical results also reveal a positive yet non-linear relationship between the scale of service activities and profitability: while initial levels of servicing result in a steep increase in profitability, a period of relative decline is observed before the positive relationship between the scale of services and profitability re-emerges. These findings suggest the presence of initial short-term gains but also indicate the existence of a ‘profitability’ hurdle; profitable growth seems feasible only to the extent that investments in service capability are translated into economies of scale. In helping to clarify the performance implications of service innovation, our findings suggest pathways to sustainable growth through servitization for manufacturing firms.     

Does the World Economy Swing National Elections?*

Do voters reward national leaders who are more competent economic managers, or merely those who happen to be in power when the world economy booms? Using data from 268 democratic elections held between 1978 and 1999, I compare the effect of world growth (luck) and national growth relative to world growth (competence). Both matter, but the effect of luck is larger than the effect of competence. Voters are more likely to reward competence in countries that are richer and better educated; and there is some suggestive evidence that media penetration rates affect the returns to luck and competence.     

The family gap in wages: What wombmates reveal

We shed new light on the effects of having children on hourly wages by exploiting access to data on the entire population of employed same-sex twins in Denmark. Our second contribution is the use of administrative data on absenteeism; the amount of hours off due to holidays and sickness. Our results suggest that childbearing reduces female hourly wages but the principal explanation is in fact mothers’ higher levels of absence. We find a positive wage premium for fathers.     

Accumulation, Technical Progress, and Increasing Returns in the Economic Growth of East Asia

Adopting homothetic variable returns to scale functional specifications, this study identifies the returns to scale in the aggregate production functions of four East Asian newly industrialized economies–Hong Kong, Korea, Singapore, and Taiwan–and the Group of Five economies based on a maximum likelihood estimation. The study finds evidence of increasing returns in the early developmental stage of the East Asian economies. Separating out the scale contribution from the non-scale factor contributions, the decomposition of the sources of East Asian economic growth differs significantly from the conventional constant returns to scale results, indicating that the role of technical progress is overestimated when constant returns to scale is assumed.     

The Nexus of Population,Energy, Innovation,and Complexity

For the past 200 years, humans have benefited from the abundant, inexpensive, and easily obtained energy of fossil fuels. Energy surpluses such as this are unusual in human history. In systems with little surplus energy, population growth is low and complexity emerges slowly due to the energetic costs it carries. On the rare occasions when energy is readily available, societies respond by growing rapidly. They must become more complex in response to the social, economic, and resource challenges of dense population. More complex societies are more expensive, requiring greater energy per capita. The process of increasing complexity necessitates greater energy production, creating a positive feedback cycle. Past societies have collapsed under such pressures. Population and complexity grew rapidly when the Industrial Revolution replaced economies based on annual solar radiation with economies fueled by fossil energy. The Green Revolution of the 20^th century is credited with preventing mass starvation, but it has made food production and sustaining population ever‐more dependent on high‐energy (low‐entropy) inputs. Some believe innovation will overcome the limitations of resources and permit unchecked growth. However, increases in complexity, innovation, and fossil energy are all subject to diminishing returns, and cannot continue to support population at current levels.     

Modeling Agglomeration and Dispersion in City and Country: Gunnar Myrdal, François Perroux, and the New Economic Geography

The "new economic geography" is a recent body of literature that seeks to explain how resources and production come to be concentrated spatially for reasons other than the standard "geographic" ones. Unlike alternative explanations of the geographic distribution of industry, the literature is not interdisciplinary. The new economic geography lies well within economics proper: it is an offspring of international trade theory, with models characterized by increasing returns, factor mobility, and transportation costs. The models explain the distribution of industry in terms of the opposition of an agglomerating force, the interaction of transportation costs and increasing returns to scale, with a dispersing force, commonly the interaction of transportation costs and a partially fixed input or output market.
Some authors outside the new economic geography (e.g., Martin 1999) have criticized it as simplistic, irrelevant, or passé. They claim it employs overly abstract analysis, prioritizes mathematical technique over realistic explanation, and is reminiscent of the much earlier works of Gunnar Myrdal and François Perroux—in comparison to which, however, it falls short.
This paper investigates the similarities and differences between the new economic geography and the work of Myrdal and Perroux, who in the previous special issue of this journal were ranked by Zafirovsky (1999, pp. 596, 598) as among the leading twentieth century economic sociologists. I examine how the techniques of analysis and intuitive explanations of agglomeration compare between these economic sociologists and the new economic geographers. The paper highlights what has been gained and what has been lost by the new economic geographers, who generally eschew interdisciplinary study.     

The impact of stakeholder heterogeneity on risk perceptions in technological innovation

Managing risk has been widely acknowledged as a crucial managerial task in the development of new technology. More recently, the acceptance of new technologies has increasingly been influenced by secondary stakeholders, some of which are difficult to identify, or whose concerns are not easily reconciled. This paper develops a conceptual framework based on the management of technology and research & development literature, stakeholder theory, risk and social judgment to describe how traditional approaches based on reducing uncertainties through estimating probabilities may not work for social uncertainties; different heuristics are needed to understand and resolve such heterogeneous stakeholder perspectives. We contribute to the discourse by describing how risk perceptions among stakeholders vary, and how this may change over time. The framework suggests that the perception of primary stakeholder towards a specific innovation is ‘Standard’ when information is well known, but becomes riskier when information is unclear. For secondary stakeholders, when there is a low degree of imperfect information, the stakeholder relationship is an ‘Irritant’ but becomes increasingly ‘Dangerous’ when information becomes ambiguous. We conclude with implications for management and future research.     

The size distribution of innovations revisited: An application of extreme value statistics to citation and value measures of patent significance

This paper focuses on the analysis of size distributions of innovations, which are known to be highly skewed. We use patent citations as one indicator of innovation significance, constructing two large datasets from the European and US Patent Offices at a high level of aggregation, and the Trajtenberg [1990, A penny for your quotes: patent citations and the value of innovations. Rand Journal of Economics 21(1), 172–187] dataset on CT scanners at a very low one. We also study self-assessed reports of patented innovation values using two very recent patent valuation datasets from the Netherlands and the UK, as well as a small dataset of patent licence revenues of Harvard University. Statistical methods are applied to analyse the properties of the empirical size distributions, where we put special emphasis on testing for the existence of ‘heavy tails’, i.e., whether or not the probability of very large innovations declines more slowly than exponentially. While overall the distributions appear to resemble a lognormal, we argue that the tails are indeed fat. We invoke some recent results from extreme value statistics and apply the Hill [1975. A simple general approach to inference about the tails of a distribution. The Annals of Statistics 3, 1163–1174] estimator with data-driven cut-offs to determine the tail index for the right tails of all datasets except the NL and UK patent valuations. On these latter datasets we use a maximum likelihood estimator for grouped data to estimate the tail index for varying definitions of the right tail. We find significantly and consistently lower tail estimates for the returns data than the citation data (around 0.6–1 vs. 3–5). The EPO and US patent citation tail indices are roughly constant over time, but the latter estimates are significantly lower than the former. The heaviness of the tails, particularly as measured by value indicators, we argue, has significant implications for technology policy and growth theory, since the second and possibly even the first moments of these distributions may not exist.     

Forecasting with equilibrium-correction models during structural breaks

When location shifts occur, cointegration-based equilibrium-correction models (EqCMs) face forecasting problems. We consider alleviating such forecast failure by updating, intercept corrections, differencing, and estimating the future progress of an ‘internal’ break. Updating leads to a loss of cointegration when an EqCM suffers an equilibrium-mean shift, but helps when collinearities are changed by an ‘external’ break with the EqCM staying constant. Both mechanistic corrections help compared to retaining a pre-break estimated model, but an estimated model of the break process could outperform. We apply the approaches to EqCMs for UK M1, compared with updating a learning function as the break evolves.     

Optimal city size,land tenure and the economic theory of clubs

In this paper, a connection is made between urban population size in the presence of increasing returns to scale, and the economic theory of clubs. It is shown that under certain conditions, the optimal size of the population is finite and that collective action are transferable concepts from the theory of clubs. The model is also solved in a closed format, i.e., including rent payments as part of total income, under two redistribution schemes. It is shown that the optimal size of the population is independent of the mode of ownership of the urban residential land, when the transportation cost function is linear.