This work describes a Gaussian Markov random field model that includes several previously proposed models, and studies properties of its maximum likelihood (ML) and restricted maximum likelihood (REML) estimators in a special case. Specifically, for models where a particular relation holds between the regression and precision matrices of the model, we provide sufficient conditions for existence and uniqueness of ML and REML estimators of the covariance parameters, and provide a straightforward way to compute them. It is found that the ML estimator always exists while the REML estimator may not exist with positive probability. A numerical comparison suggests that for this model ML estimators of covariance parameters have, overall, better frequentist properties than REML estimators. 相似文献
We study dynamic committee bargaining over an infinite horizon with discounting. In each period, a committee proposal is generated by a random recognition rule, the committee chooses between the proposal and a status quo by majority rule, and the voting outcome in period t becomes the status quo in period t + 1. We study symmetric Markov equilibria of the resulting game and conduct an experiment to test hypotheses generated by the theory for pure distributional (divide-the-dollar) environments. In particular, we investigate the effects of concavity in the utility functions, the existence of a Condorcet winning alternative, and the discount factor (committee “impatience”). We report several new findings. Voting behavior is selfish and myopic. Status quo outcomes have great inertia. There are strong treatment effects that are in the direction predicted by the Markov equilibrium. We find significant evidence of concave utility functions. 相似文献
Abstract. Recent studies on the growth effects of exchange rate regimes offer a wide range of different, sometimes contradictory results. In this paper, we systematically compare three prominent contributions in this field. Using a common data set, a common specification and common estimation methods, we argue that the contradictory findings can be explained by the fact that these studies use regime classifications which reflect fundamentally different aspects of exchange rate policy. 相似文献
In this paper, we address the topic of policy actorness in Italian foreign policy to characterize the understudied role of the President of the Italian Republic (PoR). We apply quantitative narrative analysis (QNA) as the methodological tool of our study, answering two research questions to which the academic literature has so far produced limited responses: (a) whether the PoR can be considered a relevant actor in Italian foreign policy and (b) which factors can affect the Italian PoR’s relevance in foreign policy. Considering the Italian PoR’s Diary as the unit of analysis and source of data, we study the two crucial cases of Ciampi’s presidency (1999–2006) and Napolitano’s first presidency (2006–2013). QNA allows us to quantify and compare, while maintaining an actor-centred approach, the relations of the two PoRs with the most relevant actors in foreign policy. The results of our analyses highlight the relevance of the Italian PoR figure, identifying the main areas of influence of the Italian head of state and their changes over time. We conclude providing a few hypotheses to interpret the outcomes of our analyses on the PoR’s role in Italian foreign policy.
This paper addresses the issue of measuring temporal dynamics of complex socio-economic relational systems, represented as time-dependent networks. Network dynamics is first splitted into a structural component, accounting for changes in the network topology, and a non-structural component, accounting for permutation of vertex labels. A quantitative measure of the dynamics and its components is then proposed and it is shown how it can be used to investigate and interpret the time evolution of networks. A real example is discussed, pertaining to the dynamics of a subnetwork of the Italian corporate board network. 相似文献
There is a commonly held view that firms in high‐wage/skill‐intensive sectors will tend to provide wages and working conditions that are above market‐clearing levels. This article empirically examines this claim by analysing the content of all collective agreements concluded in the resource sector in Australia after the enactment in 2006 of the Workplace Relations Amendment (Workchoices) Act. This legislation gave employers unprecedented ability to place downwards pressure on employee entitlements. In the resource sector, however, the quantitative results indicate that firms maintained, in the main, substantive standards but used extensively key regulatory provisions to gain an unprecedented level of control over both functional and numerical flexibility. 相似文献
The influence of risk aversion on the decision to become self-employed is a much discussed topic in the entrepreneurial literature.
Conventional wisdom asserts that being an entrepreneur means making risky decisions; hence more risk-averse individuals are
less likely to become entrepreneurs. In contrast to previous research, we are able to examine empirically whether the decision
of starting a business is influenced by objectively measurable risk attitudes at the time when this decision is made. Our results show that in general, individuals with lower risk aversion are more likely to become
self-employed. Sensitivity analysis reveals, however, that this is true only for people coming out of regular employment,
whereas for individuals coming out of unemployment or inactivity, risk attitudes do not seem to play a role in the decision
process.
The purpose of this paper is to apply a modified version of the income choice model to explain variations in new-firm formation across Italian provinces over the period 1985–1988. Based on a panel data of startup activity in 78 Italian provinces and using two different data bases, we find support for the overall theory of income choice where individuals choose between earning wages from an incumbent enterprise or else profits from starting a new firm. In particular, the evidence suggests that labor market conditions such as wages and the relative impact of labor dislocation, profits, and environmental factors such as the degree to which entrepreneurial networks already exist, shape the degree to which new firms are started. 相似文献