Linear Increments with Non‐monotone Missing Data and Measurement Error

Linear increments (LI) are used to analyse repeated outcome data with missing values. Previously, two LI methods have been proposed, one allowing non‐monotone missingness but not independent measurement error and one allowing independent measurement error but only monotone missingness. In both, it was suggested that the expected increment could depend on current outcome. We show that LI can allow non‐monotone missingness and either independent measurement error of unknown variance or dependence of expected increment on current outcome but not both. A popular alternative to LI is a multivariate normal model ignoring the missingness pattern. This gives consistent estimation when data are normally distributed and missing at random (MAR). We clarify the relation between MAR and the assumptions of LI and show that for continuous outcomes multivariate normal estimators are also consistent under (non‐MAR and non‐normal) assumptions not much stronger than those of LI. Moreover, when missingness is non‐monotone, they are typically more efficient.     

Semiparametric Estimation of a Change-point for Recurrent Events Data

One particular recurrent events data scenario involves patients experiencing events according to a common intensity rate, and then a treatment may be applied. The treatment might be effective for a limited amount of time, so that the intensity rate would be expected to change abruptly when the effect of the treatment wears out. In particular, we allow models for the intensity rate, post-treatment, to be at first decreasing and then change to increasing (and vice versa). Two estimators of the location of this change are proposed.     

VALIDATION OF EXPERT SYSTEMS- WITH APPLICATIONS TO AUDITING AND ACCOUNTING EXPERT SYSTEMS*

This paper proposes a set of definitions for the concepts “validation” and “assessment” applied to expert systems (ESs). It develops a framework for this validation and demonstrates the framework on existing accounting and auditing ESs to elicit some of the research issues involved in ES validation. Validation is critical to the design and implementation of decision-making ESs. In a setting where objectivity is sought and variance is avoided, validation ascertains what a system knows, knows incorrectly, or does not know. Validation ascertains the system's level of expertise and investigates the theoretical basis on which the system is based. It evaluates the reliability of decisions made by the system. The validation framework developed in this paper is research methods. It is designed to reflect the unique aspects of ESs (in contrast to other types of computer programs) and can be used by ES developers as a basis from which to perform validation and by researchers as a framework to elicit research issues in validation.     

AN EMPIRICAL ASSESSMENT OF COMPUTER-ASSISTED DECISION ANALYSIS*

Decision analysis tools often are used in semistructured and ill-structured situations. While some researchers have argued that computerized decision analysis programs may improve decision quality in such situations, research support for this assertion is weak. In this laboratory study, business students used a computerized decision-analysis program with short strategic-management cases to prepare decision reports. Independent raters' perceptions of aided and unaided decision performance were contrasted, attitudes of students toward the program were assessed, individual differences were correlated with attitudes, and the program's impact on students' perceptions of their decision processes and performance was examined. Student attitudes toward the computerized aid were favorable, and individual differences in reactions generally were as predicted. However, the program did not improve the independent ratings of students' decision reports and recommendations. These findings suggest that computerized decision aids should be adopted cautiously. If such aids result in positive user affect and heightened decision confidence without corresponding improvements in decision quality, they may be dysfunctional. Rigorous research methodologies which incorporate independent evaluations of analyses and decisions are recommended for use in future research on computerized decision-analysis programs.     

A DECISION THEORY EXAMPLE IN FOOTBALL

In the 1967 Harvard-Cornell football game, Harvard was ahead 14–0 late in the game when Cornell scored two touchdowns. On both occasions, Cornell tried and failed on the two-point conversion attempt and lost the game 14–12. Postgame arguments were divided on the merits of Cornell's strategy. For this frequently occurring scenario in college football, we derive a maximum expected utility decision rule for the decision of kicking versus running/passing based on the relative utility of a win, a tie, or a loss and the probabilities of success with a kick as opposed to a run/pass.     

Downsizing for downtown: limb lengths,toe lengths,and scale counts decrease with urbanization in western fence lizards (Sceloporus occidentalis)

Urban Ecosystems - Urbanization-induced habitat loss and alteration causes significant challenges for the survival of many species. Identifying how species respond to urbanization can yield...     

Responsibility,planning and risk management: moralizing everyday finance through financial education

The individualization, privatization and marketization of risk management represent a fundamental dimension of the financialization of everyday life. As individuals are required to engage with financial products and services as the main way of protecting themselves from risks and uncertainties, their economic welfare and security are construed as depending largely on their own financial decisions. Within this setting, the concept of financial literacy and accompanying practices of financial education have emerged as a prominent institutional field handling the formulation and communication of the attributes and dispositions that arguably constitute the proper financial actor. This article analyzes financial education programmes currently conducted by state agencies in Israel, examining the notions and principles they articulate when defining and explaining proper financial conduct. The study indicates that moral themes and categories occupy a salient place in the formulation of the character traits that constitute the desired literate financial actor. Notions of individual responsibility, planning ahead and rational risk management are presented not merely as instrumental resources, but as moral imperatives. Through these notions, the programmes moralize a broad array of everyday practices of personal finance such as saving, investing, borrowing and budget management, thereby connecting the sphere of financial matters to the domain of moral virtues. Offering a representation of particular modes of financial conduct as constitutive components of morally virtuous personhood, these practices imbue the financial field as a whole, especially its current generalized logic of individualized and marketized risk management, with moral meanings, hence contributing to the normalization and depoliticization of the financialization of everyday life.     

Value Chain Development and the Agrarian Question: Actor Perspectives on Native Potato Production in the Highlands of Peru

Value chain development seeks to integrate smallholder farmers into competitive markets to promote economic and social development. This article, conceptually based on the agrarian question, considers how the perspectives of various value chain actors, with particular focus on smallholders, have important implications for the outcomes of these market‐oriented initiatives. Utilizing Long’s concept of social interface, we present a mixed‐methods case study that analyzes how smallholders, an NGO, and agrifood corporations, including PepsiCo, partnered to establish value chains for native potatoes in the Peruvian highlands. We find that a thorough understanding of the various perspectives held by value chain actors provides important insight into why value chain initiatives have divergent trajectories. Based on the findings, we conclude that accounting for how actors are responding to development initiatives and one another helps explain development outcomes and that therefore the agrarian question remains relevant in current agricultural development discourse and practice.