Convergence Properties of the Likelihood of Computed Dynamic Models

This paper studies the econometrics of computed dynamic models. Since these models generally lack a closed‐form solution, their policy functions are approximated by numerical methods. Hence, the researcher can only evaluate an approximated likelihood associated with the approximated policy function rather than the exact likelihood implied by the exact policy function. What are the consequences for inference of the use of approximated likelihoods? First, we find conditions under which, as the approximated policy function converges to the exact policy, the approximated likelihood also converges to the exact likelihood. Second, we show that second order approximation errors in the policy function, which almost always are ignored by researchers, have first order effects on the likelihood function. Third, we discuss convergence of Bayesian and classical estimates. Finally, we propose to use a likelihood ratio test as a diagnostic device for problems derived from the use of approximated likelihoods.     

Response to “Revisiting ISO 14000 Diffusion: A New ”Look“ at the Drivers of Certification”

In Corbett and Kirsch (2001), we used a simple regression in an exploratory investigation of drivers of global diffusion of ISO 14000 certification. We found that ISO 9000 certification levels, environmental treaties ratified, and exports as a proportion of GDP were the main significant variables, where the environmental measure may be moderated by GDP per capita. In his replication study, Vastag (2004, in this issue) analyzes the same data using more visual techniques, specifically regression trees, and finds support for the significance of ISO 9000 certification levels and environmental treaties ratified, but not for export‐propensity. Vastag raises a number of relevant methodological issues, to which we add some perspectives here.     

Comment on “Commitment vs. Flexibility”

This comment corrects two results in the 2006 Econometrica paper by Amador, Werning, and Angeletos (AWA), that features a model in which individuals face a trade‐off between flexibility and commitment. First, in contrast to Proposition 1 in AWA, we show that money‐burning can be part of the ex ante optimal contract when there are two states. Second, in contrast to Proposition 2 in AWA, we show that money‐burning can be imposed at the top (in the highest liquidity shock state), even when there is a continuum of states. We provide corrected versions of the above results.     

A Reply to Williamson's “Outsourcing …”

A recent article by Oliver Williamson essentially comprises a critique of supply chain management (SCM) from the perspective of his own field, transaction‐cost economics. Here is one reader's response. SCM can indeed be faulted for inflated rhetoric, among other sins. I believe, however, that the two fields have much to learn from each other.     

The global “war for talent”

In this paper we examine the “global war for talent,” the factors that impact it, and organizations' responses to it. Using a comprehensive search of more than 400 contemporary academic and business press articles, the paper reviews relevant research and reassesses the “talent war.” We posit that the dominant approaches to the “talent war” based on a scarcity state of mind and action, often characterized by a tactical and exclusive top talent or “star” focus, are being challenged by the emergence of a more evolutionary paradigm. This new paradigm adopts more strategic, innovative, cooperative and generative approaches which we describe as creative ‘talent solutions.’ The paper also highlights implications for future research, teaching and development in the field.     

TOWARD A “NEW ARCHITECTURE” FOR POM

The field of POM is steadily expanding its scope. This allows us to pursue interesting new fields of inquiry and makes us ever more relevant to the needs of practitioners. But it also increases the risk that over time our efforts will become fragmented and unfocused, causing us to slowly lose our sense of community and break up into separate camps. In this paper I ask, “What kind of new organizing framework, or ‘architecture,’ will allow us to maintain our sense of community as our interests diverge?” I describe the experience of one academic organization that faced a similar problem several years ago and how the situation was resolved. This experience leads us to propose a possible solution to Pom's emerging problem: engage with real operations managers and focus our efforts on helping them deal with the actual problems they are facing in today's complex and fast‐changing world.