Optimal Harvesting of an Age-Structured Schooling Fishery

Biologists have criticized traditional biomass models in fishery economics for being oversimplified. Biological stock assessment models are more sophisticated with regard to biological content, but rarely account for economic objectives. This study includes a full age-structured population model for studying schooling fisheries and extends the delayed difference approach used in earlier studies. We take the total harvest as the choice variable, resulting in a simple analytical structure. The model produces optimal steady states that may be higher or lower compared to the delayed-difference formulation. The model is applied to the Baltic sprat fishery. Both ecological and harvesting cost data support specifying Baltic sprat as a schooling fishery. Given nonlinear harvesting costs, the optimal solution is a path toward a steady state with smooth annual harvest and population age structure. Sensitivity analysis shows that the optimal solution is highly dependent on the population level of the sprat’s main predator Baltic cod. A linear cost function and an interest rate below 9 % imply pulse fishing instead of smooth continuous harvesting. Given nonlinear harvesting cost, the optimal steady state yield is rather insensitive to changes in the interest rate. However, under a high cod scenario, interest rates of 10 % or higher implies that no optimal steady state exists.     

Measuring and forecasting mobile game app engagement

Monetization strategies in the large and strongly growing mobile app space must go beyond traditional purchase revenue as most mobile apps are now free to download. One key marketing innovation allows mobile app publishers to monetize ongoing engagement — in-app advertising.We study ongoing user engagement with a mobile app after the initial download decision using the $40 billion mobile gaming industry as an example. Our study investigates and forecasts user engagement after the initial download aiming to help publishers to monetize their engagement via in-app advertising. We leverage a novel dataset containing user-level engagement for 193 mobile games and propose a hierarchical Poisson model on a mobile-game level. We find significant usage heterogeneity across the mobile games studied and generate forecasts publishers can use when trying to monetize engagement via pre-sold contracts.     

Gas storage valuation under limited market liquidity: an application in Germany

Natural gas storages may be valued by applying real options theory. However, it is crucial to take into account that most evolving gas markets, like the German spot market, lack liquidity. This implies that large-scale operation of storages reduces the achievable operating margin since storage operators will pay higher prices for injected gas and earn less on withdrawn gas. Optimal storage operation will take this into account. In this context, considering storage operators as price takers does not account for interdependencies of storage operations and market prices. This paper offers a novel approach to storage valuation taking into account the effect of management decisions on market prices. The methodology proposed within this paper determines the optimal production schedule and value by determining the stochastic differential equation describing the storage value and then applying a finite difference scheme. We find that limited liquidity lowers the storage value and reduces withdrawal and injection amounts. Further, we observe decreasing reservation prices for injection and withdrawing for growing illiquidity resulting in a left shift of injection and withdrawing threshold prices.     

Athleticism and the reproduction of gender and ethnic marginality

Our paper explores the construction of ethnic and gender identities through sport and physical education, arguing that the social attitudes of women and members of ethnic minorities to sport helps to define their marginal position in society. We analyse the literature with respect to ethnicity, gender and sport within the framework of recent ethnographic research, and show how gender and ethnic factors markedly affect attitudes to sport. The wider implications of these attitudes are examined and related to work, unemployment and marginal social status. Attitudes to sport are seen to be significant in establishing attitudes to leisure as a whole, which is discussed in terms of social reproduction and the state. We extend the notion of marginality to take account of the importance of leisure behaviour in explaining and justifying the status of women and ethnic minorities in society.     

Intended brand associations: Do they really drive consumer response?

Brand managers exhibit considerable effort to define intended brand associations to anchor in consumers' minds. They follow a credo deeply rooted in branding literature: intended brand associations drive consumer response and brand equity. This article investigates the benefits of a strong overlap of actual consumer brand associations and management-intended brand associations (brand association match). The article presents results from two large-scale studies (3353 and 1201 respondents) involving one consumer goods and one service brand with multiple operationalizations of consumer response (attitudinal and behavioral). The results show that consumers with high brand association match show more positive brand response. However, after accounting for the valence of associations match does not add explanatory power. This outcome challenges a key foundation of brand management. The discussion identifies reasons why match may not be necessary to achieve response and provides arguments why the results do not imply free play for brand managers.     

A note on estimating the divisional cost of capital for diversified companies: an empirical evaluation of heuristic-based approaches

This note provides an empirical analysis of the potential for heuristic-based approaches to derive a divisional cost of equity from a firm's total cost of capital. Since an empirical relationship between fundamental information and systematic risk has previously been shown in other studies, idiosyncratic information on risk and performance ought to serve as a good proxy to calculate divisional adjustments. Two practically used, heuristic-based approaches are tested and a significant relationship is found between one of the measures and CAPM beta. This method may offer a plausible and comparatively uncomplicated method for adjusting a firm's total cost of capital for divisional use.     

Discrete credit barrier models

The model introduced in this article is designed to provide a consistent representation for both the real-world and pricing measures for the credit process. We find that good agreement with historical and market data can be achieved across all credit ratings simultaneously. The model is characterized by an underlying stochastic process that takes on values on a discrete lattice and represents credit quality. Rating transitions are associated with barrier crossings and default events are associated with an absorbing state. The stochastic process has state-dependent volatility and jumps which are estimated by using empirical migration and default rates. A risk-neutralizing drift is estimated to consistently match the average spread curves corresponding to all the various ratings.     

Justifying top management pay in a transitional economy

We investigate some aspects of top management pay in China's listed firms. We find positive pay and performance sensitivities and elasticities for top executives. In terms of magnitude, these sensitivities are similar to those reported in U.S. firms during the 1970s. However, the pay and performance relation is slightly weaker for firms located in less developed provinces. We also find that the pay disparities between top managers and employees are positively related to a firm's performance. Thus, it appears that any deviation away from a manager-worker compensation norm has to be justified by superior firm performance. In additional analyses, we find that managers' perquisites are not related to performance.     

From Returns to Tweets and Back: An Investigation of the Stocks in the Dow Jones Industrial Average

A sizeable percentage of investors are using social media to obtain information about companies (Cogent Research [2008]). As a consequence, social media content about firms may have an impact on stock prices (Hachman [2011]). Various studies utilize social media content to forecast stock market-related factors such as returns, volatility, or trading volume. The objective of this article is to investigate whether a bidirectional intraday relationship between stock returns and volatility and tweets exists. The study analyzed 150,180 minute-by-minute stock price and tweet data for the 30 stocks in the Dow Jones Industrial Average over a random 13-day interval from June 2 to June 18, 2014 using a BEKK-MVGARCH methodology. Findings indicate that 87% of stock returns are influenced by lagged innovations of the tweets data, but there is little evidence to support that the direction is reciprocal, with only 7% of tweets being influenced by lagged innovations of the stock returns. Results further show that the lagged innovations from 40 percent of stock returns affect the current conditional volatility of the tweets, while 73 percent of tweets affect the current conditional volatility of stock returns. Moreover, there is strong evidence to suggest that the volatility originating from the returns to the tweets persists for 33 percent of stocks; the volatility originating from the tweets to the returns persists for 73 percent of stocks. Last, 53 percent of stocks exhibit both immediate and persistent impacts from returns to tweets, while 90 percent of stocks exhibit both immediate and persistent impacts from tweets to returns. These results may help traders achieve superior returns by buying and selling individual stocks or options. Also, asset and mutual fund managers may benefit by developing a social media strategy.     

Contextual Framing and Monetary Incentives in Field Experiments on Risk Preferences: Evidence from German Farmers

Recent studies cast doubt on the ability of abstract experiments to predict decision‐making in the field. Thus, scholars have argued for more ‘realism’ by introducing context to field experiments. Yet, such realism may work against the induced values of monetary incentives in economic experiments. It is an open question whether contextual framing works best with or without inducing values, through methods such as the use of monetary incentives. Using a sample of 146 German farmers, we compare experimentally the predictive power of a framed lottery in an agricultural context vs. using an abstract version. For one half of the sample, lotteries are incentivised; for the other half, they are hypothetical. Although risk preferences differ between treatments, all four lottery tasks correlate poorly with farmers’ real‐world use of risk management instruments such as harvest or hail insurance. Subjects who start with an agricultural framing are willing to take significantly greater risks in the lotteries. More generally, our findings cast doubt on the ability of lottery tasks to predict risk‐taking in the field.