Motivating job design as a factor in open source governance

Successful open source software (OSS) projects can be considered as examples of how ambitious work results can be achieved in web-based collaboration even when monetary incentives are low or absent. While former explorations of motivational processes in OSS projects primarily focused on person-oriented aspects such as motives, interests, and expected benefits of contributors, job-related factors have been largely neglected. After discussing the limitations of a person-oriented focus, a research perspective is suggested that concentrates on job design and work context in OSS based on frameworks from work psychology. A theoretical analysis is presented discussing job characteristics of successful OSS projects as potential explanations of the high motivation of OSS contributors. Compared to a person-oriented perspective, the results of a job-oriented approach might be better transferable to other projects (both OSS and “closed source” software development) and provide guidelines for the governance of successful web-based collaboration.

Bayesian clustering for row effects models

We deal with two-way contingency tables having ordered column categories. We use a row effects model wherein each interaction term is assumed to have a multiplicative form involving a row effect parameter and a fixed column score. We propose a methodology to cluster row effects in order to simplify the interaction structure and to enhance the interpretation of the model. Our method uses a product partition model with a suitable specification of the cohesion function, so that we can carry out our analysis on a collection of models of varying dimensions using a straightforward MCMC sampler. The methodology is illustrated with reference to simulated and real data sets.     

Culture and Institutions: Economic Development in the Regions of Europe

Does culture have a causal effect on economic development? The data on European regions suggest that it does. Culture is measured by indicators of individual values and beliefs, such as trust and respect for others, and confidence in individual self determination. To isolate the exogenous variation in culture, we rely on two historical variables used as instruments: the literacy rate at the end of the 19th century, and the political institutions in place over the past several centuries. The political and social history of Europe provides a rich source of variation in these two variables at a regional level. The exogenous component of culture due to history is strongly correlated with current regional economic development, after controlling for contemporaneous education, urbanization rates around 1850, and national effects. (JEL: O10, F10, P10, N13)     

GOVERNMENT SPENDING COMPOSITION,TECHNICAL CHANGE,AND WAGE INEQUALITY

In this paper we argue that government spending played a significant role in stimulating the wave of innovation that hit the U.S. economy in the late 1970s and in the 1980s, as well as the simultaneous increase in inequality and in education attainments. Since the late 1970s U.S. policymakers began targeting commercial innovations more directly and explicitly. We focus on the shift in the composition of public demand toward high‐tech goods, which, by increasing the market‐size of innovative firms, functions as a de facto innovation policy tool. We build a quality‐ladders non‐scale growth model with heterogeneous industries and endogenous supply of skills, and show that an increase in the technological content of public spending stimulates R&D, raises the wage of skilled workers, and, at the same time, stimulates human capital accumulation. A calibrated version of the model suggests that government policy explains between 12% and 15% of the observed increase in wage inequality in the period 1976–1991. (JEL: E62, J31, O33, O41)     

采用动态闪烧法快速准确可靠地检测土壤中含氮量

动态闪烧法是分析土壤及植物中氮元素的理想技术。据实验数据显示,这种技术重复性好,且改变样品种类时无记忆效应,可达到氮这种重要营养元素的完全检测。采用这种检测技术可分析从低到高的宽浓度范围的含氮量,且准确度高,无基质效应。     

Identification and Inference in Nonlinear Difference‐in‐Differences Models

This paper develops a generalization of the widely used difference‐in‐differences method for evaluating the effects of policy changes. We propose a model that allows the control and treatment groups to have different average benefits from the treatment. The assumptions of the proposed model are invariant to the scaling of the outcome. We provide conditions under which the model is nonparametrically identified and propose an estimator that can be applied using either repeated cross section or panel data. Our approach provides an estimate of the entire counterfactual distribution of outcomes that would have been experienced by the treatment group in the absence of the treatment and likewise for the untreated group in the presence of the treatment. Thus, it enables the evaluation of policy interventions according to criteria such as a mean–variance trade‐off. We also propose methods for inference, showing that our estimator for the average treatment effect is root‐N consistent and asymptotically normal. We consider extensions to allow for covariates, discrete dependent variables, and multiple groups and time periods.     

Up in the Skies? The Relationship between Body Height and Earnings in Germany

Abstract. This paper analyses whether taller workers earn more than their shorter counterparts. Using GSOEP data from 1991 to 2002, earnings functions are estimated for male and female workers for both West and East Germany. The Hausman–Taylor IV estimator is applied to account for unobservable heterogeneity including also time‐invariant indicators. The results do not imply wage differentials based on height for female workers and male East German workers. For the height range up to 195 cm there is, however, a wage premium associated with stature for male workers from West Germany of about 4 per cent for each additional standard deviation increment in height.     

Adaptive confidence intervals of desired length and power for normal means

In all empirical or experimental sciences, it is a standard approach to present results, additionally to point estimates, in form of confidence intervals on the parameters of interest. The length of a confidence interval characterizes the accuracy of the whole findings. Consequently, confidence intervals should be constructed to hold a desired length. Basic ideas go back to Stein (1945) and Seelbinder (1953) who proposed a two-stage procedure for hypothesis testing about a normal mean. Tukey (1953) additionally considered the probability or power a confidence interval should possess to hold its length within a desired boundary. In this paper, an adaptive multi-stage approach is presented that can be considered as an extension of Stein's concept. Concrete rules for sample size updating are provided. Following an adaptive two-stage design of O’Brien and Fleming (1979) type, a real data example is worked out in detail.     

Decentralized Trading With Private Information

The paper studies how asset prices are determined in a decentralized market with asymmetric information about asset values. We consider an economy in which a large number of agents trade two assets in bilateral meetings. A fraction of the agents has private information about the asset values. We show that, over time, uninformed agents can elicit information from their trading partners by making small offers. This form of experimentation allows the uninformed agents to acquire information as long as there are potential gains from trade in the economy. As a consequence, the economy converges to a Pareto efficient allocation.     

On a strengthening of the indifference zone approach to a generalized selection goal

The problem of selecting s out of k given compounts which contains at least c of the t best ones is considered. In the case of underlying distribution families with location or scale parameter it is shown that the indiffence zone approach can be strengthened to confidence statements for the parameters of the selected components. These confidence statements are valid over the entire parameter space without decreasing the infimum of the probability of a correct selection.