Criminal Justice Analysis, Comparative Methods, Module 4, Parts 1, 2, and 3

• NCJ Number: 81176
• Author(s): Anonymous
• Date Published: Unknown
• Length: 0 pages
• Grant Number(s): 78-MU-AX-0030
• Sponsoring Agency: US Dept of Justice
• Publication Format: Film
• Publication Type: Statistics
• Language: English
• Country: United States of America
• Note: *This document is currently unavailable from NCJRS. 3 videotapes, total running time 2 hours and 10 minutes, color, 1 inch. Part of the Criminal Justice Analysis Course held at Washburn University of Topeka.

Annotation

This videotape of a working classroom session on statistical analysis begins with a lecture on a number of comparative techniques used to describe crime and system problems and concludes with instructor-supervised exercises and calculations.

Abstract

Four basic types of indices -- the concentration index, the distribution index, the density index, and the unit share index -- are discussed in terms of their applicability for comparative analysis and possible biases in their use, as well as the likely sources where data can be obtained. The Sellin-Wolfgang Index represents an attempt to achieve crime seriousness weighting. The usefulness as well as the pitfalls of weighting according to a seriousness scale are pointed out. The basics of bivariate descriptions are introduced and the building of two-way cross classification tables is illustrated. Emphasis is placed on the interpretation of cross tabulations. An explanation follows of how to plot bivariate data on scattergrams and how to interpret the relationship of the data, clustering, and outliers. The presentation concludes with examples of statistical maps and their usefullness for geographic reference and in simplifying and visualizing the results of complex data analysis. A pin map, a grid map, a smoothed contour map, and a three-dimensional contour map illustrate types of maps useful for representing crime statistics. Pin and grid maps can be constructed manually, without the aid of a computer, and may prove useful in highlighting a particular point. A decisionmaking chart summarizes the comparative measures presented and leads from the expression of two variables to the form of index numbers through their weighting by means of the seriousness scale to their representation in a picture. While a nominal or ordinal scale is expressed in a percentaged cross tabulation table, an interval or ratio scale can be transfered to a scattergram. If geography is important, the comparative tool to be chosen is the statistical map. For the instructor's guide to this course, see NCJ 81170. For other videotaped sessions, see NCJ 81171-5, 81177-82, and 81186.