Probabilistic forecasting of heterogeneous consumer transaction–sales time series

We present new Bayesian methodology for consumer sales forecasting. Focusing on the multi-step-ahead forecasting of daily sales of many supermarket items, we adapt dynamic count mixture models for forecasting individual customer transactions, and introduce novel dynamic binary cascade models for predicting counts of items per transaction. These transaction–sales models can incorporate time-varying trends, seasonality, price, promotion, random effects and other outlet-specific predictors for individual items. Sequential Bayesian analysis involves fast, parallel filtering on sets of decoupled items, and is adaptable across items that may exhibit widely-varying characteristics. A multi-scale approach enables information to be shared across items with related patterns over time in order to improve prediction, while maintaining the scalability to many items. A motivating case study in many-item, multi-period, multi-step-ahead supermarket sales forecasting provides examples that demonstrate an improved forecast accuracy on multiple metrics, and illustrates the benefits of full probabilistic models for forecast accuracy evaluation and comparison.     

Assessment of meaningful change in routine outcome measurement (ROM) with a combination of a longitudinal and a ‘classify and count’ approach

To assess significant changes of health status in people receiving health care, distribution-based and anchor-based methods have been proposed. However, there is no real consensus on what method is the best for evaluating clinically meaningful change. To maximize the internal and external validity of outcome assessment, we propose combining two approaches as recommended by recent practical guidelines on this field. Specifically, we suggest applying longitudinal hierarchical linear models on subgroups of patients showing reliable change and reliable and clinically significant change. This combined approach improved the model’s ability (1) to quantify the magnitude of changes to be reliable and clinically meaningful and (2) to select significant predictors of changes. An empirical application on a prevalence sample of Italian outpatients attending four community mental health services was done. A cross-sectional model and three longitudinal models were applied on the entire study sample and reliable and clinically meaningful change subsamples to investigate the magnitude of change and the predictive effect on outcomes of clinical, socio-demographic and process variables on different patients’ subgroups. Differences were found suggesting that both the statistical method and the sample used to calculate individual changes affect the estimates. The main conclusion is that ignoring the longitudinal data structure or including patients with unreliable change at the follow-up might result in misleading inferences that can alter the real magnitude of changes and the contributions of predictors. The approach proposed provides robust feedback to clinicians on clinically significant change and can be recommended in outcome studies and research.     

Does the labor-income process contain a unit root? Evidence from individual-specific time series

Calibrations of models related to life-cycle behavior of consumption and saving often invoke the important assumption of a unit root in individuals׳ labor-income process. We for the first time test this assumption using methods for univariate time series. Based on longitudinal register data from 1968 to 2005, we first estimate an autoregressive model for each individual using a method for approximately median-unbiased estimation. We then exploit the resulting distribution of the individual-specific estimates to draw inference about the presence of a unit root. Results indicate that earnings for the representative worker are governed by a process where shocks to earnings have moderate persistence and are both economically and statistically significantly different from having permanent effects. These results question the heavy use of unit-root processes for earnings.     

On the exact distribution of the Fisher-Behren’-Welch statistic

Summary For testing the significance of the difference between the unknown means of two normal populations having different unknown variances, we have the known Fisher-Behren’s-Welch test statistic. Several expressions for the distribution of this test statistic are available, and this paper is yet another attempt in the same direction. However, the expression given here appears to be, perhaps, more elegant and straight-forward than the ones available at present.     

Levers of logistics service providers’ efficiency in urban distribution

This paper identifies the most important factors that influence the productivity of the urban fleet of a Logistics Service Provider (LSP). Through a regression analysis on a dataset from distribution warehouses of a single LSP, three main levers are shown to have significant impacts on productivity, namely the network design, the vehicle loading strategy, and the business environment wherein the operations are carried out. This paper contributes to bridge the gap about the lack of works addressing the efficiency of LSPs operating in urban areas, by performing a detailed empirical analysis instead of taking an aggregated company perspective.     

On the distribution of the desirability index using Harrington’s desirability function

The concept of desirability is a means for complexity reduction of multivariate quality optimization. This paper provides a theoretical breakthrough regarding desirability indices, which application fields were formerly limited primarily by the lack of its distribution. Focussed are the distributions of Harrington’s desirability functions and different types of the desirability index.     

The influence of entrepreneurs’ immigrant status and time on the perceived likelihood of exporting

We contribute in this paper to the scant literature on the factors and conditions influencing the development of different perceptions of potential international opportunities for immigrant and native entrepreneurs in the pre-internationalization phase. Specifically, we investigate what factors influence the perceived likelihood entrepreneurs have of exporting. Building on entrepreneurial intentions and opportunity-based entrepreneurial processes, we propose a cognitive account of perceived likelihood of exporting based on entrepreneurs’ perceptions of the desirability and feasibility of export opportunities. We investigate how the immigrant status (i.e., individual characteristics) and time (i.e., contextual factors) influence the relationship between the desirability and feasibility of exporting, and entrepreneurs’ perceived likelihood of exporting. We employ an experimental design on a matched-pair sample of 108 native and immigrant entrepreneurs in domestic technology-based firms. The results are a unique account of the cognitive antecedents of the perceived likelihood of exporting under different temporal conditions, comparing immigrant and native entrepreneurs. We discuss theoretical and practical implications.

     

Changes in the distribution of house prices over time: Structural characteristics,neighborhood, or coefficients?

Quantile hedonic house price function estimates imply that appreciation rates were higher between 1995 and 2005 for high-priced homes in Chicago. Decompositions of temporal changes in the house price distribution suggest that the types of homes sold and their location do not account for the change in the price distribution. Rather, higher appreciation rates for high-priced homes are explained by differences in the quantile regression coefficients over time.     

Changes in the distribution of house prices over time: Structural characteristics,neighborhood, or coefficients?

Quantile hedonic house price function estimates imply that appreciation rates were higher between 1995 and 2005 for high-priced homes in Chicago. Decompositions of temporal changes in the house price distribution suggest that the types of homes sold and their location do not account for the change in the price distribution. Rather, higher appreciation rates for high-priced homes are explained by differences in the quantile regression coefficients over time.     

What's in a broken promissory obligation? Developing and testing a multiple component form measure of psychological contract breach

While the literature has suggested the possibility of breach being composed of multiple facets, no previous study has investigated this possibility empirically. This study examined the factor structure of typical component forms in order to develop a multiple component form measure of breach. Two studies were conducted. In study 1 (N = 420) multi-item measures based on causal indicators representing promissory obligations were developed for the five potential component forms (delay, magnitude, type/form, inequity and reciprocal imbalance). Exploratory factor analysis showed that the five components loaded onto one higher order factor, namely psychological contract breach suggesting that breach is composed of different aspects rather than types of breach. Confirmatory factor analysis provided further evidence for the proposed model. In addition, the model achieved high construct reliability and showed good construct, convergent, discriminant and predictive validity. Study 2 data (N = 189), used to validate study 1 results, compared the multiple-component measure with an established multiple item measure of breach (rather than a single item as in study 1) and also tested for discriminant validity with an established multiple item measure of violation. Findings replicated those in study 1. The findings have important implications for considering alternative, more comprehensive and elaborate ways of assessing breach.     

A drunk and her dog: a spurious relation? Cointegration tests as instruments to detect spurious correlations between integrated time series

A significant correlation between integrated time series does not necessarily imply a meaningful relation. The relation can also be meaningless, i.e. spurious. Cointegration is sometimes illustrated by the metaphor of ‘a drunk and her dog’. The relation between integrated processes is meaningful, if they are cointegrated. To prevent spurious correlations, integrated series are usually transformed. This implies a loss of information. In case of cointegration, these transformations are no longer necessary. Moreover, it can be shown that cointegration tests are instruments to detect spurious correlations between integrated time series. This paper compares the Dickey–Fuller and the Johansen cointegration test. By means of Monte Carlo simulations, we found that these cointegration tests are a much more accurate alternative for the identification of spurious relations compared to the rather imprecise method of utilizing the R ²-and DW-statistics recommended by some authors. Furthermore, we demonstrate that cointegration techniques are precise methods of distinguishing between spurious and meaningful relations even if the dependency between the processes is very low. Using these tests, the researcher is not in danger of either neglecting a small but meaningful relation or regarding a relation as meaningful which is actually spurious.     

Developing a ‘European’ model of human resource management

The concept of human resource management (HRM) has been much debated in the literature. Space limitations preclude an examination of that debate here, but it is clear that the concept developed initially from work in the United States of America in the 1960s and 1970s and since then has been adopted increasingly in the academic literature, by consultancy services and in organizational terminology. The terminology spread from the USA firstly into the developed English speaking world and recently - and more partially - into Europe. Is the concept, as opposed to the terminology, applicable in Europe? This paper argues that the organizational autonomy on which the subject is propounded in the United States is not espoused in Europe. A range of subject areas in which organizations in Europe are supported/constrained by external factors are analysed, thus challenging the validity of the American model. This raises the need to consider different conceptual approaches to HRM: a new model of the concept which would encompass EuroHRM is proposed.     

Sensemaking of environmental commitment: a socio-historical contextualization of post-Soviet managers’ views

The different social contexts and historical backgrounds of countries in which companies operate may influence how their managers understand and apply the concept of environmental commitment. Thus, the understanding of environmental commitment in the post-communist societies of Central and Eastern Europe can be expected to be different from the Western markets. This study sheds light on these issues by analyzing managerial stories about environmental commitment in Russia. It explains how managers’ sensemaking is shaped by the Soviet socio-historical context. This study contributes to the limited literature on environmental commitment in post-communist societies and provides a link between environmental commitment and sensemaking research, thus responding to recent calls for a clarification of the microfoundations of corporate social responsibility.     

‘Gatekeepers’ of Islamic financial circuits: Analysing urban geographies of the global Shari’a elite

This paper analyses the importance of ‘Shari’a scholars’ in the Islamic Financial Services (IFS) sector, which has been a growing global practice since the 1970s. Based on Shari’a Law, IFS firms provide banking, finance and insurance respecting faith-based prohibitions on interest, speculation and risk taking. Although IFS firms operate across a variety of scales and involve a range of actors, this paper focuses on the transnational capacities of Shari’a experts employed by IFS firms. These scholars use their extensive knowledge of Shari’a Law to assess the ‘Islamic’ character of a firm's operations, and assist the development of Shari’a-compliant products. As they embody necessary entry-points into Islamic circuits of knowledge and authority, members of what we dub the ‘global Shari’a elite’ can be regarded as ‘gatekeepers’ of Islamic financial circuits. Drawing on a comprehensive data source we present a geographical analysis of Shari’a board membership, nationality and educational background of 253 Shari’a scholars. The results show that the global Shari’a elite connects a limited number of IFS hubs (e.g. Dubai, Kuala Lumpur, Kuwait City, Manama, and London) to knowledge and authority networks falling outside ‘mainstream’ business and service spheres.     

Past price ‘memory’ in the housing market: testing the performance of different spatio-temporal specifications

Recent methodological developments provide a way to incorporate the temporal dimension when accounting for spatial effects in hedonic pricing. Weight matrices should decompose the spatial effects into two distinct components: bidirectional contemporaneous spatial connections; and unidirectional spatio-temporal effects from past transactions. Our iterative estimation approach explicitly analyses the role of time in price determination. The results show that both spatio-temporal components should be included in model specification; past transaction information stops contributing to price determination after eight months; and limited temporal friction is exhibited within this period. These findings highlight the decidedly non-linear temporal patterns of such information effects.     

Estimation of technical change and price elasticities: a categorical time–varying coefficient approach

We propose a categorical time-varying coefficient translog cost function, where each coefficient is expressed as a nonparametric function of a categorical time variable, thereby allowing each time period to have its own set of coefficients. Our application to U.S. electricity firms reveals that this model offers two major advantages over the traditional time trend representation of technical change: (1) it is capable of producing estimates of productivity growth that closely track those obtained using the Törnqvist approximation to the Divisia index; and (2) it can solve a well-known problem commonly referred to as “the problem of trending elasticities”.     

Non-self-averaging of a two-person game with only positive spillover: a new formulation of Avatamsaka’s dilemma

In this game [Aruka in Avatamsaka game structure and experiment on the web. In: Aruka Y (ed) Evolutionary controversies in economics. Springer, Tokyo, pp 115–132, 2001], selfishness may not be determined even if an agent selfishly adopts the strategy of defection. Individual selfishness can only be realized if the other agent cooperates, therefore gain from defection can never be assured by defection alone. The sanction by defection as a reaction of the rival agent cannot necessarily reduce the selfishness of the rival. In this game, explicit direct reciprocity cannot be guaranteed. Now we introduce different spillovers or payoff matrices, so that each agent may then be faced with a different payoff matrix. A ball in the urn is interpreted as the number of cooperators, and the urn as a payoff matrix. We apply Ewens’ sampling formula to our urn process in this game theoretic environment. In this case, there is a similar result as in the classic case, because there is “self-averaging” for the variances of the number who cooperate. Applying Pitman’s sampling formula to the urn process, the invariance of the random partition vectors under the properties of exchangeability and size-biased permutation does not hold in general. Pitman’s sampling formula depends on the two-parameter Poisson–Dirichlet distribution whose special case is just Ewens’ formula. In the Ewens setting, only one probability α of a new entry matters. On the other hand, there is an additional probability θ of an unknown entry, as will be argued in the Pitman formula. More concretely, we will investigate the effects of different payoff sizes from playing a series of different games for newly emerging agents. As Aoki and Yoshikawa (Non-self-averaging in macroeconomic models: a criticism of modern micro-founded macroeconomics, Economics Discussion Papers 2007-49. . November 26, 2007) and Aoki (J Econ Interact Coord 3:1–3, 2008) dealt with a product innovation and a process innovation, they criticized Lucas’ representative method and the idea that players face micro shocks drawn from the same unchanged probability distribution. In the light of Aoki and Yoshikawa (Non-self-averaging in macroeconomic models: a criticism of modern micro-founded macroeconomics, Economics Discussion Papers 2007-49. . November 26, 2007), we show the same argument in our Avatamsaka game with different payoffs. In this setting, innovations occurring in urns may be regarded as increases of the number of cooperators in urns whose payoffs are different.     

The role of entrepreneurship education as a predictor of university students’ entrepreneurial intention

Using Ajzen’s theory of planned behavior and Shapero’s entrepreneurial event model as well as entrepreneurial cognition theory, we attempt to identify the relationship between entrepreneurship education, prior entrepreneurial exposure, perceived desirability and feasibility, and entrepreneurial intentions (EI) for university students. The data were collected from a survey of ten universities; we received 494 effective responses. We used probit estimation to show that perceived desirability significantly impacts EI whereas there is no significant impact from perceived feasibility. There is a significant negative impact from exposure (which is surprising) and a significant positive impact from entrepreneurship education. Males and people from technological universities and/or backgrounds have higher EI than females and people from other universities and backgrounds. There are also significant positive interactive effects by gender, university type, and study major on the relationship between entrepreneurship education and EI.