A note on unbiasedness in ratio estimation

The method of ratio estimation for estimating the population mean ? of a characteristic y when we have auxillary information on a characteristic x highly correlated with y, consists in getting an estimator of the population ratio R = ?/X? and then multiplying this estimator by the known population mean X?. Though efficient, ratio estimators are in general biased and in this article we review some of the unbiased ratio estimators and discuss a method of constructing them. Next we present the Jackknife technique for reducing bias and show how the generalized Jackknife could be interpreted by the same method.     

Implemented as intended? Recording family worker activities in a Families First program

In evaluating family preservation services, it is important not only to study the service outcomes and the family characteristics, but also what actually happens during the treatment. This requires a program model. This article describes how a program model works, prescribes how workers should carry it out, and describes how researchers should measure the program's characteristics. The authors use data from Families First in The Netherlands to test the model. Results show that the method of the program meets the specified characteristics. The results are important for treatment, policy, education, and evaluation research.     

The voter who wasn’t there: Referenda,representation and abstention

We analyze single binary-choice voting rules and identify the presence of the No-Show paradox in this simple setting, as a consequence of specific turnout or quorum conditions that are included in actual rules. Since these conditions are meant to ensure a representative outcome, we formalize this concern and reach our main result: no voting rule can ensure representation if abstention is possible, unless restrictive assumptions are made on the preference domain of abstainers. We then focus on the main referendum systems and show that appropriate restrictions do make them compatible with representation. The main purpose of our paper is, however, to provide a tool for referendum design: rather than imposing arbitrary restrictions on the preference domain of non-voters, we recommend instead that a conscious choice be made on how abstention is to be interpreted and that this choice be used to derive the corresponding referendum rule.The idea for this paper started with some jocose but insightful notes written by José João Marques da Silva at the time of the first referendum held in Portugal (1998). When José João passed away in August 2000, ISEG lost a bright, interested and friendly scholar. May we dedicate this paper to his memory. This paper was presented at the 2002 Annual Meeting of the Public Choice Society and Economic Science Association, San Diego, CA and a preliminary version was presented at the 2001 Annual Meeting of the European Public Choice Society, Paris. We would like to thank Mathew Braham, Moshé Machover, Eric Maskin, Vincent Merlin, Hannu Nurmi, Katri Sieberg, Frank Steffen, and two anonymous referees for helpful comments. The usual proviso applies.     

Public attitudes toward the use of psychiatric medications for children

Psychiatric medication use for children has increased dramatically over the past three decades. Despite substantial media attention to the issue, little is known about how the lay public feels about the use of psychiatric medications for children. Drawing on theories of medicalization, we describe and analyze Americans' attitudes towards the use of psychiatric medications generally and Prozac specifically for children described as having three types of behavioral problems. Using data from the 1998 General Social Survey's Pressing Issues in Health and Medical Care Module, we find that more Americans (57%) are willing to use psychiatric medications for children who have expressed suicidal statements than for "oppositional" behaviors (34.2%) or for hyperactivity (29.5%). Across the board, respondents are less willing to give Prozac than the general class of psychiatric medications. While socio-demographics do little to identify Americans with differing positions, the strongest and most consistent correlates of willingness to give psychiatric medications to children are trust in personal physicians, general attitudes towards psychiatric medications, and the respondent's expressed willingness to take psychiatric medications herself or himself.