A gradient boosting approach to the Kaggle load forecasting competition

We describe and analyse the approach used by Team TinTin (Souhaib Ben Taieb and Rob J Hyndman) in the Load Forecasting track of the Kaggle Global Energy Forecasting Competition 2012. The competition involved a hierarchical load forecasting problem for a US utility with 20 geographical zones. The data available consisted of the hourly loads for the 20 zones and hourly temperatures from 11 weather stations, for four and a half years. For each zone, the hourly electricity loads for nine different weeks needed to be predicted without having the locations of either the zones or stations. We used separate models for each hourly period, with component-wise gradient boosting for estimating each model using univariate penalised regression splines as base learners. The models allow for the electricity demand changing with the time-of-year, day-of-week, time-of-day, and on public holidays, with the main predictors being current and past temperatures, and past demand. Team TinTin ranked fifth out of 105 participating teams.     

DEFINING RELEVANT MARKETS FOR PHARMACEUTICALS

To identify the relevant product markets for Swedish pharmaceuticals, a spatial econometrics approach is employed. First, we calculate Moran's Is for different market definitions and then we use a spatial Durbin model to determine the effect of price changes on quantity sold of own and competing products. As expected, the results show that competition is strongest between close substitutes; however, the relevant product markets for Swedish pharmaceuticals extend beyond close substitutes down to products included in the same class on the four‐digit level of the Anatomic Therapeutic Chemical system as defined by the World Health Organization. The spatial regression model further indicates that increases in the price of a product significantly lower quantity sold of that product and in the same time increase the quantity sold of competing products. For close substitutes (products belonging to the same class on the seven‐digit level of the Anatomic Therapeutic Chemical system), as well as for products that, without being close substitutes, belong to the same therapeutic/pharmacological/chemical subgroup (the same class on the five‐digit level of the Anatomic Therapeutic Chemical system), increased competition is also visible after 1 July 2009 when the latest policy changes with regards to pharmaceuticals have been implemented in Sweden.     

Going green,going clean: Lean‐green sustainability strategy and firm growth

Despite the widespread recognition of the paybacks of “going green” and “going clean,” limited research has focused on the impact of lean‐green strategy on firm growth. In this study, we contribute to strategy and environmental sustainability literatures by investigating the possibility that the influence on lean‐green strategy and firm growth is driven by different levels of industry competition, managerial power, and family ties. Using panel data from 732 firms in four major industrialized economies (the United States, Germany, France, and the United Kingdom), we found that lean‐green strategy positively relates to firm growth and this relationship is amplified at higher levels of competition, managerial power, and family ties. Theoretical and practical implications of the study are also discussed.     

The impact of environmental regulation on Chinese spatial development

We examine the relationship between environmental regulation and spatial development in China. Exploiting changes in national pollution standards for three industries, ammonia, paper and cement, we measure the impact of environmental regulation on industry productivity. Our results suggest that national pollution standards do not affect industry productivity, but they reallocate productivity spatially. We show that regulated industries located in developing cities increase their productivity compared to similar industries in other cities. This means that environmental regulation affects the spatial distribution of technology in China and might influence long‐term spatial development by reducing geographical disparities.     

Relative age effects in political selection

We exploit a regression discontinuity design to provide causal evidence of the relative age effect (RAE) on a long-run adult age outcome: Political selection. We find strong evidence of the RAE in politics in Finland. However, the effect is heterogeneous: We find that male candidates born early in the calendar year have a significantly higher probability of getting elected to the parliament but no similar RAE applies to female candidates nor to municipal elections. Moreover, this effect only takes place in the most competitive parliamentary districts and is present only for some parties. We also find that in all the groups where the RAE does not exist, early-born candidates are under-represented suggesting attrition of talent in the candidate placement. Overall, our results show that seemingly artificial cutoffs imposed by the government have persistent consequences even on the selection to the highest positions of power within a society.     

US small retail businesses’ perception of competition: Looking through a lens of fear,confidence, or cooperation

The U.S. retail industry has undergone dramatic changes, leading to the closing of brick-and-mortar retail stores on a large scale. Understanding perceived market competition among small retail businesses may help explain why certain businesses survive or fail in the altered retail environment. This study investigates small retail businesses' perceptions of competition within/outside the community, underlying reasons for their perceptions, and variations in perceptions by different business characteristics. Contrary to common expectations, we found that more than half of businesses interviewed were optimistic in the face of competition. Our data reveal two salient underlying reasons for pessimism and five for optimism. These perceptions tended to differ by operational locality (urban clusters vs. urban areas), business revenues, and innovativeness. Based on the findings, we developed propositions and a framework of small businesses' perceived competition and sustainable competitive advantage. We discussed theoretical and practical implications for small retail businesses’ sustainable growth in the challenging retail environment.     

Political competition,tax salience and accountability. Theory and evidence from Italy

This paper argues that electoral competition may hinder rather than foster political accountability, especially when elected officers can choose among a number of tax instruments. We develop a political agency model showing that politicians in more competitive jurisdictions use less salient tax instruments more intensely. Defining salience as visibility or, analogously, as voters' awareness of the costs associated with specific government revenue sources, we argue that voters are less likely to hold politicians to account for the associated tax burden of a less salient instrument. This in turn implies that strategic politicians will more heavily rely on less salient revenue sources when electoral competition is stronger. Using data on Italian municipal elections and taxes over a 10-year period, we determine the degree of salience of various tax instruments, including property taxes (high salience) and government fees for official documents (low salience). We then show that mayors facing stronger competition for re-election use less salient tax instruments more intensely.     

Global energy forecasting competition 2017: Hierarchical probabilistic load forecasting

The Global Energy Forecasting Competition 2017 (GEFCom2017) attracted more than 300 students and professionals from over 30 countries for solving hierarchical probabilistic load forecasting problems. Of the series of global energy forecasting competitions that have been held, GEFCom2017 is the most challenging one to date: the first one to have a qualifying match, the first one to use hierarchical data with more than two levels, the first one to allow the usage of external data sources, the first one to ask for real-time ex-ante forecasts, and the longest one. This paper introduces the qualifying and final matches of GEFCom2017, summarizes the top-ranked methods, publishes the data used in the competition, and presents several reflections on the competition series and a vision for future energy forecasting competitions.     

Protection for sale under monopolistic competition: Beyond the CES

We extend the protection for sale model of Grossman and Helpman (1994) by introducing a general model of monopolistic competition with variable markups and incomplete pass-through. We show that the structure of protection emerging in the political equilibrium not only depends on the weight attached by the government to consumer welfare when making its policy decision, but also on the degree of market power of firms and on the terms-of-trade variations due to the degree of pass-through. Our results highlight the importance of preferences in shaping the structure of protection and are consistent with the occurring of protectionism also in unorganized industries.