Robust methods in econometrics

This survey of recent developments in robust estimation and inference is directed primarily toward econometricians. It is argued that many of the techniques in common use in econometrics are highly sensitive to unverified hypotheses. Recent progress in designing alternative robust procedures is described and some prospects for future developments are discussed.     

Titin--springing back to youth?

Mutations in the muscle protein titin have been linked to dilated cardiomyopathy, a condition in which the heart chambers are enlarged and blood is ineffectively pumped, in humans and in animal models. This protein, which is a component of sarcomeres, provides essential scaffolding for other muscle proteins and acts as a spring to confer passive elasticity on the cardiomyocyte. Several titin isoforms exist, and they display varying size and degrees of elasticity. We review two interesting reports that show how variations in titin isoforms might be implicated in cardiac failure.     

Estimating the Structure of Agricultural Investment: A Stochastic- Coefficients Approach

Two approaches, a flexibie-accelerator model and a stochastic-coefficients alternative, are used to estimate the structure of aggregate agricultural investment. Structural estimates of the adjustment rates for each model differ. The stochastic-coefficients model, however, performs better in out-of-sample forecasting.     

Diversity in sociology: Problem or solution?

Some of sociology’s recent internal critics (e.g., Turner and Turner, 1990; Halliday and Janowitz, 1992; Collins, 1986; Gans, 1990; Crane and Small, 1992) suggest that the discipline's diversity of theoretical, methodological and substantive foci leave it in a weakened position for achieving individual and collective ends. Other sociologists (e.g., D'Antonio, 1992; Roos and Jones, 1993; Stacey and Thorne, 1985) argue that substantive diversity has made the discipline attractive to a greater variety of previously underrepresented groups, particularly women, groups that have, in turn, contributed to sociology’s substantive diversity. This paper reports on a content analysis of 2,016 articles from North American sociology journals in 1936, 1956, 1976, and 1996 as well as from chemistry, anthropology, economics, political science, and psychology journals in 1996. The analysis focused on a number of, often contradictory, hypotheses drawn from the competing views of sociology's diversity with respect to its substantive concerns and its gender composition. It finds, for instance, that there is more substantive diversity in today's sociology journal articles than there was earlier, at least when diversity is measured in terms of fields that are reputed to be attractive to women. This may not be surprising, since more women are writing sociology journal articles than ever before. Moreover, the substantive diversity seems to be related to more, not less, funding of sociological research. It is, of course, a trite remark — one made more frequently by sociologists than by their gibing critics — that sociology has not yet come to the development which commands from its adherents wholehearted agreement as to the objectives to be aimed at, the field to he limited, and the methods to be used. Gladys Bryson, 1936     

Are elderly drivers a road hazard?: Problem definition and political impact

Elderly drivers are increasing in number and some statistics show they are more likely to be involved in fatal accidents than all other age groups but those under 25. States have attempted to address the problem in various ways, but very few have required mandatory retesting at license renewal for those beyond a particular age. Why have so few states chosen to act? The key is how the issue is framed for the public and decision makers. Several phases of problem definition are explored to explain the political dynamics of the older driver issue: incidence, causality, severity, crisis labeling, problem population characteristics, and linkage of values to the issue and solutions. Based upon this analysis, it is not surprising that elder interest groups have been successful in containing policy initiatives designed to restrict elderly driving.     

The foundations of econometrics-are there any

The conclusions of alogically consistent economic theory which strictly adheres to Aristotle's axioms of logic are factually true if its sufficient conditions are all factually true. Alternatively, if a conclusion of such a theory is false, then at- least one of its assumptions is false. Unfortunately, the factual truth of sufficient conditions cannot be established because the problem of induction i s impossible t o solve. It is algo true that the falsity of a conclusion cannot be established in the presence of uncertainty. While the philosophy of instrumentalism applied to sufficient and logically consistent explanations may provide useful solutions to immediate practical problems, the principles of simplicity, parsimony and profligacy--all of them requiring conditional deductive arguments--are useless as criteria for model choice.     

The Use of Lay Assessors

This paper reports on some findings from a research study conductedby the authors for the Commission for Social Care Inspection.It examines the reasons for the involvement of lay assessorsand perceptions of the effectiveness of lay assessors in specificregulatory functions.