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NCJRS Abstract

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NCJ Number: 219228 Find in a Library
Title: Use of Bayes Coefficients to Assess the Racial Bias-Hair Analysis Conjecture for Detection of Cocaine in Hair Samples
Journal: Forensic Science Communications  Volume:9  Issue:2  Dated:April 2007  Pages:1-12
Author(s): Tom Mieczkowski; Chris Sullivan; Michael Kruger
Date Published: April 2007
Page Count: 12
Document: HTML
Type: Report (Study/Research)
Format: Document (Online)
Language: English
Country: United States of America
Annotation: This study tested the hypothesis that self-reported cocaine use will parallel the outcomes of both urine and hair assays for cocaine regardless of the subject's race.
Abstract: The hypothesis was supported, which undermines persistent arguments that hair-assay methods for detecting cocaine use are racially biased against African-Americans. The ratios for all assays compared with self-reports were consistent across their respective time frames, and none of the ratios were significantly different from one another. Although a superficial inspection of the data may seem to indicate a race bias for hair analysis, indepth analysis determined otherwise. The ratios of all of the Bayes posterior probabilities were in the same direction, i.e., that being African-American was associated with a relatively higher probability of being assay-positive; however, being African-American was also associated with a higher probability of self-reported cocaine use in both short and long time frames. The hair and urine specimens along with self-report data on cocaine use were collected during the operation of the Pinellas County Drug Study (Florida), a drug-monitoring program conducted at the Pinellas County Jail from 1991 through 1993. Approximately twice a year the project staff interviewed close to 300 male and female arrestees at the booking stage of arrest. The data analyzed comprised a base of 1,857 cases. Of those asked, 92.9 percent provided a urine sample, and 84.9 percent provided a hair sample. There were no notable differences in rates of self-reported responses. The analysis compared the ratio of the probability of having a positive outcome for all three measures: self-report, urine assay, and hair assay. Researchers used an analysis based on the application of Bayes' theorem. 4 tables and 26 references
Main Term(s): Criminology
Index Term(s): Black/African Americans; Cocaine; Drug detection; Florida; Hair and fiber analysis; Racial discrimination; Self reported crimes
Note: Downloaded July 23, 2007.
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