External Validity in Policy Evaluations That Choose Sites Purposively

Evaluations of the impact of social programs are often carried out in multiple sites, such as school districts, housing authorities, local TANF offices, or One‐Stop Career Centers. Most evaluations select sites purposively following a process that is nonrandom. Unfortunately, purposive site selection can produce a sample of sites that is not representative of the population of interest for the program. In this paper, we propose a conceptual model of purposive site selection. We begin with the proposition that a purposive sample of sites can usefully be conceptualized as a random sample of sites from some well‐defined population, for which the sampling probabilities are unknown and vary across sites. This proposition allows us to derive a formal, yet intuitive, mathematical expression for the bias in the pooled impact estimate when sites are selected purposively. This formula helps us to better understand the consequences of selecting sites purposively, and the factors that contribute to the bias. Additional research is needed to obtain evidence on how large the bias tends to be in actual studies that select sites purposively, and to develop methods to increase the external validity of these studies. © 2012 by the Association for Public Policy Analysis and Management.     

Histological correlates of post mortem mitochondrial DNA damage in degraded hair

We have assessed the histological preservation of naturally degraded human hair shafts, and then assayed each for levels of amplifiable mitochondrial DNA and damage-associated DNA miscoding lesions. The results indicate that as sample histology is altered (i.e. as hairs degrade) levels of amplifiable mitochondrial DNA decrease, but no correlation is seen between histology and absolute levels of mitochondrial DNA miscoding lesions. Nevertheless, amplifiable mitochondrial DNA could be recovered across the complete range of the histological preservation spectrum. However, when template copy number is taken into consideration, a correlation of miscoding lesions with histology is again apparent. These relationships indicate that a potential route for the generation of misleading mitochondrial sequence data exists in samples of poor histology. Therefore, we argue that in the absence of molecular cloning, the histological screening of hair may be necessary in order to confirm the reliability of mitochondrial DNA sequences amplified from hair, and thus represents a useful tool in forensic mitochondrial DNA analyses.     

Nursing home quality-of-care cases after Mikes v. Straus

The quality of care rendered to residents of nursing facilities continues to gain attention from legislators, regulators, and the courts. Advocates for improvements in the quality of care by government-funded healthcare providers have identified the False Claims Act (FCA) as a potent tool. The Second Circuit decision in Mikes v. Straus might be viewed as a barrier to FCA claims against nursing facilities. Any impediment imposed by this decision, however, is limited by the facts of the case; the authors believe that carefully-crafted pleadings can enable litigants to rely upon the FCA in pursuing quality-of-care claims against nursing facilities.     

INTRODUCTION

This directory summarizes the responses of 13 nations to questions about the state ot policy studies research and teaching in those nations. While policy studies is not an exclusively American development, not many countries are as involved in this area as American scholars and universities.