| NCJ Number: |
91870  |
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| Title: |
Before-and-After Experiment With a Baseline Period of Random Duration - Analysis of a Contingent Experimental Design |
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| Author(s): |
T R Willemain |
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| Corporate Author: |
Massachusetts Institute of Technology
Operations Research Ctr
United States of America |
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| Date Published: |
1978 |
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| Page Count: |
21 |
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| Sponsoring Agency: |
Massachusetts Institute of Technology
Cambridge, MA 02139
National Institute of Justice/
Rockville, MD 20849
NCJRS Photocopy Services
Rockville, MD 20849-6000
US Dept of Justice
US Dept of Justice NIJ Pub
Washington, DC 20531 |
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| Grant Number: |
78 NI-AX-0007 |
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| Publication Number: |
OR 079-78 |
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| Sale Source: |
National Institute of Justice/
NCJRS paper reproduction
Box 6000, Dept F
Rockville, MD 20849
United States of America
NCJRS Photocopy Services
Box 6000
Rockville, MD 20849-6000
United States of America |
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| Document: |
PDF |
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| Language: |
English |
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| Country: |
United States of America |
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| Annotation: |
This paper introduces a simple 'contingent experimental design' and outlines how the contingent design would operate and how it would be evaluated. |
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| Abstract: |
The familiar 'before-and-after' type of experiment is modified so that the duration of the 'baseline' period, rather than being fixed before the experiment, is made contingent on the experimenter's prior estimate of the experimental impact and on the baseline data as they appear. At the conclusion of each day of the baseline period, a decision is made as to whether to terminate the baseline at that time, weighing the costs of extending the baseline by one day against the benefits of better estimating the experimental impact. An analytic framework is proposed for making this decision and for comparing the contingent design against an alternative having a baseline period of fixed duration. Equations, figures, and three references are supplied. (Author abstract modified) |
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| Index Term(s): |
Research methods |
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| Note: |
Working Paper |
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To cite this abstract, use the following link:
http://www.ncjrs.gov/App/publications/abstract.aspx?ID=91870 |
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