EDA for HLM: Visualization when Probabilistic Inference Fails

e-mail: jwbowers{at}umich.edu (corresponding author) e-mail: kwdrake{at}umich.edu Nearly all hierarchical linear models presented to politicalscience audiences are estimated using maximum likelihood undera repeated sampling interpretation of the results of hypothesistests. Maximum likelihood estimators have excellent asymptoticproperties but less than ideal small sample properties. Multilevelmodels common in political science have relatively large samplesof units like individuals nested within relatively small samplesof units like countries. Often these level-2 samples will beso small as to make inference about level-2 effects uninterpretablein the likelihood framework from which they were estimated.When analysts do not have enough data to make a compelling argumentfor repeated sampling based probabilistic inference, we showhow visualization can be a useful way of allowing scientificprogress to continue despite lack of fit between research designand asymptotic properties of maximum likelihood estimators.     

The Economic Evaluation of Policing Activity: An Application of a Hybrid Methodology

This paper advances a hybrid police cost function that synthesises the proactive/preventive and response/reactive methodologies from the criminology literature. The model presents a coherent estimation process that can help in the allocation of scarce resources to police forces and also enable economists, government organisations and criminologists to assess the scale and technical efficiency of forces. This hybrid model uses response survey data for a sample of English and Welsh police forces in which relative efficiency rankings are contrasted with relative performance measures produced by the Audit Commission. We find that there are considerable divergences in police force's scale and technical efficiency during 1997/98 and 1998/99 utilising non-parametric techniques.     

Testing Application of Geographical Information Systems,Forensic Geomorphology and Electrical Resistivity Tomography to Investigate Clandestine Grave Sites in Colombia,South America

Colombian forensic investigators required assistance locating clandestine burials of missing persons related to human right atrocities from 14 years ago. Geoscientific search methods were trialled, including a predictive spatial statistical model, using various input and database information, to select the most likely grave locations in difficult mountainous terrain. Groundwork using forensic geomorphology, near-surface geophysics (ERT) and subsequent probing identified suspect burial positions. One site was in mountainous terrain and the other in former school grounds, both difficult to access and in poor weather conditions. In the mountainous area, a negative resistivity anomaly area was identified and intrusively investigated, found to be a buried rock. In school grounds, after MESP and intelligence were used to identify a burial site, surface depressions were identified, and ERT datasets collected over the highest priority depression; intrusive investigations discovered a hand-dug pit containing animal bones. This approach is suggested for Latin American searches.     

Essential medicolegal death investigation services: standardization of a survey instrument based on the Essential Public Health Services

The National Academy of Sciences recommends that states assess the performance of medicolegal death investigation agencies. To aid in performance assessment, we adapted an instrument based on the CDC's 10 Essential Public Health Services by translating the terminology to that of essential medicolegal death investigation services. This produced a survey that could be used to standardize reporting practices and services of agencies. To validate the instrument, a stratified random sample of 12 death investigation chiefs in 12 states was interviewed. This sample represented both medical examiner and coroner jurisdictions within the varying medicolegal structures. A cognitive testing process elicited how well participants could respond to and interpret the survey questions. The response was favorable in that the respondents agreed that given specific revisions toward question clarification, the instrument would be a useful and relevant tool for assessing system performance.