Mean value theorem for convex functions

Closed proper convex functions have many properties in common with differentiable functions such as continuity and one-sided directional derivatives. In this paper it is shown that there exists a mean value theorem for such functions with the gradient vector in the differentiable case replaced by an element of the subdifferential in the convex case.Under compactness of the isoquant sets, (minus) the cost functions are convex and with the theorem above it is easy to show that under incomplete specialization and constant returns to scale the prices of international goods determine uniquely the prices of domestic goods if the isoquant sets are linearly independent.     

Identification with latent variables

This is an essay on a unified approach to the identifiability problem in static models with and without hidden endogenous variables. As is well known, when some of these variables are unobserved, the prior information requirements for models when all endogenous variables are observed, are still there. In addition, extra prior information that takes the place of the means and covariances of the missing variables will have to be supplied directly or indirectly by the statistical researcher. In the paper we characterize the quality and quantity of the required information for the general linear static model and apply it when the model is i) an econometric demand and supply model with missing observations on the quantity transacted, ii) a factor analysis model with observed characteristics of the test takers and iii) a LISREL Model without fixed exogenous variables. With unknown true parameters, the exact rank conditions are seldom verifiable but we do recommend an implementable check-list that is adequate for almost all parameters.     

Having a creative day: Understanding entrepreneurs' daily idea generation through a recovery lens

Prior research has shown that trait creativity is important for becoming an entrepreneur and successful in business. We explore a new perspective by investigating how recovery from work stress influences entrepreneurs' daily idea generation, a key aspect of creativity. Physiological and mental recovery enables the cognitive processes of creative problem-solving. Moreover, differences in mental recovery processes help to explain age-related changes in entrepreneurs' creativity. Multilevel analyses based on 415 daily data from 62 entrepreneurs support our predictions. Our study introduces a new “state” perspective to understanding entrepreneurs' creativity, and highlights the critical role of recovery processes for idea generation.     

Conjugate small country production equilibrium concepts

Conjugacy theory is utilized and developed to develop an interpretation of the production equilibrium in general equilibrium in terms of the properties of sectoral value added functions and in terms of the relative influence of each sector on all other sectors in a small country's economy. The exact relationship between the comparative static system thus analyzed and the one traditionally built on equilibrium in terms of the vector of factor prices and gross output levels is delineated. The major contributions to the theory of effective protection are also illuminated.     

On the Same Side of the Faultline: Inclusion in the Leader's Subgroup and Employee Performance

Extending theory on faultlines and subgroups, we argue that faultlines splitting a team into homogeneous subgroups can have different effects on team members' individual performance, depending on different intra‐subgroup processes. Specifically, we propose that the effect of faultline strength on individual performance depends on whether a team member's subgroup includes the team leader. Building on the notion of faultline triggers, we further propose that organizational crises exacerbate this interaction because they make social support by the team leader especially important. We tested these assumptions with objective performance data collected over a period of four years from 3263 financial consultants (325 teams) while controlling for the effects of relational demography. Results showed that in teams with strong faultlines, consultants' performance decreased to a lesser extent in crisis years if the consultants shared a subgroup with their team leader. Thus, faultlines had different effects on team members from different subgroups.     

Entrepreneurs’ achieved success: developing a multi-faceted measure

Firm performance is typically measured via objective financial indicators. However, researchers increasingly acknowledge that entrepreneurs do not measure their success solely in financial terms but that a range of often subjective indicators matter to them. This article contributes to the debate on entrepreneurial performance by studying how entrepreneurs assess their achieved success. ‘Entrepreneurs’ achieved success’ was conceptualized as a multi-faceted construct that includes entrepreneurs’ self-reported achievement of firm performance, workplace relationships, personal fulfilment, community impact, and personal financial rewards. It was measured via the Subjective Entrepreneurial Success–Achievement Scale (SES-AS). Over the course of three studies (N?=?390) the factorial structure of ‘entrepreneurs’ achieved success’ was established and largely replicated in two cultures. Based on a nomological network, we documented relationships among ‘entrepreneurs’ achieved success’, quasi-objective indicators of firm performance, and entrepreneurs’ financial satisfaction, creativity, and health. Based on our research, we propose a new conceptual framework to study performance in the context of entrepreneurship. This framework acknowledges both the success criteria that entrepreneurs wish to achieve and those that they actually achieve, and extends our understanding of firm performance.