ON THE INDEPENDENCE OF THE SAMPLE MEAN AND TRANSLATION-INVARIANT STATISTICS FOR MATRIX NORMAL DISTRIBUTIONS

We present an explicit characterization of the joint dependency structure of an n×p matrix normal random matrix such that the p-dimensional sample mean vector is independent of all translation invariant statistics.     

Optimal Times to Contact Sample Households

Finding a suitable respondent at home is an essential and expensivecomponent of a household survey. This article reports on theresults of a study of the probabilities of finding someone aged14 or older at home and discusses the application of such datato survey design and budgeting.     

An evaluation of the tandem configuration automated guided vehicle system

The performance of a tandem automated guided vehicle (AGV) system is compared with that of conventional AGV track systems. In the tandem system the track is divided into non-overlapping, single-vehicle closed loops. Using simulation it is shown that, because of trips requiring delivery across loops, the tandem system has a higher expected travel time per load and thus a greater average time in system. When the loads are delivered within the original loop only, the tandem system has a lower average time in system than in conventional systems, although the difference is modest. Track layout appears to influence the average time in system much more than docs the dispatching rule invoked. The success of the tandem system is highly dependent on approximately even AGV utilization, which may be difficult to obtain in practice.     

Does IO Economics Really Make the Case for Investments in IT: A Rejoinder

The preceding critique [1] of the paper “The Information Problems in Organizations: A Research Model for the Value of Information and Information Systems” [3], reaches general conclusions with respect to the original paper and the applicability of economics to MIS research. These conclusions are based on arguments developed at a different level of analysis than that used in the original paper, and without considering the goals and intent of the original paper. The differences between the critique and the original paper are highlighted.     

Social Return on Investment of an Innovative Employment Option for Persons with Developmental Disabilities

Common Ground Co‐operative (CGC) provides training, administrative, and job coach support to five social enterprises for which persons with developmental disabilities are the non‐share‐capital partners. This study examines the use of social return on investment (SROI) as a means of determining the value of program impacts related to quality‐of‐life changes for enterprise partners and their families. The process of conducting this SROI analysis is described and analyzed in terms of its utility in employment services for persons with developmental disabilities.     

The Invisible Village: An Exploration of Undergraduate Student Mothers’ Experiences

This study explored the experiences of mothers in college using a qualitative design. Results showed that a lack of financial resources was the chief barrier for student mothers in their educational pursuits while social/emotional support was the most important contributor to student mothers’ success in college. Participants relied heavily on student loans to cover costs of childcare or family to help watch their children. Role conflict experienced by student mothers has implications on family and college retention. Implications of this study included the adaptation and revisions of policies at the state and federal levels in addition to implications at the university level. Limitations of the study included a lack of racial and ethnic diversity and only including student mothers currently enrolled in college. Several recommendations for future research are described.     

Government Capital,Intimate and Community Social Capital,and Food Security Status in Older Adults with Different Income Levels

Whether government‐based forms of food assistance such as the Supplemental Nutrition Assistance Program (SNAP), communal efforts including food pantries, aid from friends and family, or alternative means such as gardening are the appropriate means to reduce the prevalence of household food insecurity is a continuous source of policy contention. To inform this debate, we examine the relative importance of these forms of food assistance and acquisition to a sample of U.S. older adults from the 2010 Brazos Valley Health Assessment of central Texas households that have been stratified by income eligibility for SNAP, low‐income SNAP ineligibility, and above low income status. To identify how membership in these socioeconomic groups constrains household capacity to acquire sufficient food to maintain an adequate and healthy diet, we explore the varied associations of assets received from government; communal and intimate social networks; and alternative food sources such as gardening, hunting, and fishing with household food security across socioeconomic status, while examining the importance of place of residence on the use of capital assets. SNAP participation was the only specific capital asset associated with all levels of food insecurity for both SNAP‐eligible and ineligible low‐income groups, thus emphasizing the continued importance of food assistance among poverty‐level older adults.     

A KNOWLEDGE-BASED DSS FOR MANAGERIAL PROBLEM DIAGNOSIS

A knowledge-based system supporting managerial problem diagnosis is described. The system provides the capability to monitor values of selected variables for problem situations. When problems are located, a list of problem symptoms is delivered to a problem processor for structuring and diagnosis. Problem structuring is based on a combination of concepts from expert systems and structural modeling. User assertions about cause-effect relationships between pairs of variables are maintained in a semantic network. Problem diagnosis uses the relationships in the semantic network to construct causation trees, the branches of which represent potential explanations of the problem symptoms. Mathematical models are constructed based on causation-tree branches, and values from the data base are used to test whether the model confirms the diagnosis. If so, the source of the problem has been located and it is then up to the user to resolve the problem. If the model fails to explain the problem, the model apparently is deficient and the user may perform “what if…” type scenarios in attempts to improve the model and search for problem causes. Realistic applications in the accounting and health care areas are discussed.     

Job queues, discrimination, and affirmative action

If employers have different Becker-type discrimination coefficients for different demographic groups, then the implementation of affirmative action may have a differential impact on those groups. We estimate two vector autoregressive models of the U.S. economy, including the unemployment rates of four demographic groups. We find that a job queue existed before the implementation of affirmative action and that affirmative action changed the ordering of the job queue in manner that had a negative impact on nonwhite males. We find evidence that affirmative action may have increased the unemployment rate of nonwhite males by increasing their duration of unemployment.