Non-convex Technologies and Cost Functions: Definitions,Duality and Nonparametric Tests of Convexity

This contribution is the first systematic attempt to develop a series of nonparametric, deterministic technologies and cost functions without maintaining convexity. Specifically, we introduce returns to scale assumptions into an existing non-convex technology and, dual to these technologies, define non-convex cost functions that are never lower than their convex counterparts. Both non-convex technologies and cost functions (total, ray-average and marginal) are characterized by closed form expressions. Furthermore, a local duality result is established between a local cost function and the input distance function. Finally, nonparametric goodness-of-fit tests for convexity are developed as a first step towards making it a statistically testable hypothesis. An erratum to this article is available at .     

Incomplete markets, labor supply and capital accumulation

Endogenous labor supply decisions are introduced in an equilibrium model of limited insurance against idiosyncratic shocks. Unlike in the standard case with exogenous labor (e.g. [Aiyagari, S.R., 1994. Uninsured idiosyncratic risk and aggregate saving. Quarterly Journal of Economics 109, 659-684; Huggett, M., 1997. The one-sector growth model with idiosyncratic shocks: steady states and dynamics. Journal of Monetary Economics 39, 385-403]), labor supply is likely to be lower than under complete markets. This is due to an ex post wealth effect on labor supply (rich productive agents work fewer hours) that runs counter the precautionary savings motive. As a result, equilibrium savings and output may be lower under incomplete markets. It is also found that long-run savings remain finite even when the interest rate equals the inverse of the discount factor.     

Code and conduct in French cuisine: Impact of code changes on external evaluations

We study the effects of organizational code‐preserving and code‐violating changes on external evaluations by third parties—an essential but under‐studied strategic outcome. We define code‐preserving changes as a variation in the firm's product range that preserves the social code within which the firm positions its offering. By contrast, a code‐violating change corresponds to a variation in the product range that breaks with past codes and embraces another social code. Our analyses of French haute cuisine restaurants show that code‐preserving changes and code‐violating changes have positive effects on external evaluations. Both effects decline with prior evaluations received by the organization, but only the effect of code‐violating changes is reduced with age. Moreover, external evaluations improve when restaurants undertake more code‐preserving changes than their direct competitors but decline when they make more code‐violating changes than competitors. These results enable us to derive implications for research on strategic change, strategic groups, and strategic social positioning. Copyright © 2007 John Wiley & Sons, Ltd.     

Impact of Stressful Situations on Salespersons' Gestures

Interest: This research analyses the influence of situations on salespersons’ gestures and behaviors. This research contributes to this underresearched field by exploring the impact of stressful versus nonstressful situations on salespersons’ personal behavior.

Methods: This research is based on 1,205 gestures observed during 382 sales calls that averaged 11 minutes with 382 salespersons. Half were in stressful situations, and half were in nonstressful situations. This study focuses on pharmaceutical products (drugs) in the medical field, with 95 doctors, 6 judges, 304 average performing salespersons, 39 high performers, and 39 low performers. This study shows how salespersons’ behaviors vary depending on stressful and nonstressful situations. This research also articulates a new field of sales research that is understudied by researchers and suggests new training trends in sales management.

Objective: The objective is to answer questions such as “Does stress influence salespersons’ behavior, and what are the gestures most affected by such situations?” To examine the effects of training on gestures, an experiment with 97 salespersons was conducted during a sales training session. This experiment measured whether salespersons trained on gestures behaved differently than those who were untrained.

Results: In general, stressful or nonstressful situations caused real differences in gestural behavior. In particular, the best salespersons performed the largest number of gestures during stressful situations. For example, stressful situations increased the mechanical or emotional gestures in leg movements or the number of glances.     

Three decades of productivity change in French beef production: a Färe‐Primont index decomposition

The Färe‐Primont index is used to evaluate total factor productivity (TFP) change and its components for a sample of French suckler cow farms in grassland areas in 1985–2014. The results reveal an increase in TFP of 6.6 per cent over the whole observation period, with technological progress being the major source of productivity growth. Meanwhile, efficiency decreased. Farms experienced great technological progress from 1991 to 2000. From a methodological point of view, the comparison with results obtained with Malmquist indexes shows similar trends but different magnitudes, with the Malmquist index overestimating the TFP and technological changes compared to the Färe‐Primont index. In addition, the use of a sequential approach that restricts technological change to being positive or null allows for the precise calculation of technology changes, disregarding the effects of external conditions that are captured in efficiency changes. Finally, the estimation of full dimensional efficient facets (FDEFs) that guarantees the positivity of all shadow prices used to assess the mix efficiency component of TFP change is promising.     

From Social Pacts to Productivity Boards

Market solutions can be a way for small deregulated states like the Baltics to grow, but they are not a viable path for the EMU area as a whole or for the larger countries like France, Germany or Italy. As most of the challenges have to be addressed at the national level only, an interaction of flexible institutions (as the social pacts were) in coordination with developing European institutions (like a European unemployment scheme) can offer a more stable environment for growth.     

Agent-Based Reallocation Problem on Social Networks

Resource reallocation problems aim to determine an allocation maximizing a given objective function. Numerous applications are based on the assumption of restricted contacts between entities but, up to now, studies have been based on unrealistic contexts. Indeed, most of the time, agents are omniscient and/or have complete communication abilities, which are not plausible assumptions in many applications. A solution does not only consist in an optimal allocation, but in a sequence of transactions changing an initial allocation into an optimal solution. We show that the individual rationality does not allow the achievement of socially optimal allocations, and we propose a more suitable criterion: the sociability. Our method provides a sequence of transactions leading to an optimal allocation, with any restriction on agents’ communication abilities. Provided solutions can be viewed as emergent phenomena.     

Do rating agencies’ decisions impact stock risks? Evidence from European markets

This article analyses the effect of rating agencies’ decisions on stock risks for European issuers concerning five kinds of events. Our approach is an extension of dummy variable regression event study methodology, using a GARCH(1,1) estimation to capture simultaneously the impact on both systematic and specific stock risks. This new methodology allows us to obtain both global results by categories of rating decisions and individual results, event by event. We document, globally, a positive impact of upgrading on systematic risk, a negative impact of rating confirmation on specific risk, and no significant impact in all other cases. Regarding event-by-event results, the proportion of rating actions exhibiting a significant effect on risk is almost always observed between 20% and 30%. The weak evidence of a global effect on systematic risk may be due to the lack of informational content of the rating decisions on the stocks’ risk, or the existence of rebalancing effects between systematic and idiosyncratic risks. Furthermore, it should be noticed that the decline in volatility in case of a rating affirmed is an insight of the certification role played by the agencies.