Russel-Research-Method-in-Anthropology

126 Chapter 5
Time 1 Time 2
Assignment Pretest
Intervention Posttest
O X O
1 2
Figure 5.1f. The one-group pretest-posttest design.
skill-building program (midwives, coal miners, kindergarten teachers, etc.) get
any effect from the program?
Peterson and Johnstone (1995) studied the effects on 43 women inmates of
a U.S. federal prison of an education program about drug abuse. The participants
all had a history of drug abuse, so there is no random assignment here.
Peterson and Johnstone measured the participants’ health status and perceived
well-being before the program began and after the program had been running
for nine months. They found that physical fitness measures were improved for
the participants as were self-esteem, health awareness, and health-promoting
attitudes.
The Two-Group Posttest-Only Design without Random Assignment
The two-group posttest-only design without random assignment design
is shown in figure 5.1g. This design, also known as the static group compari-
Time 1 Time 2
Assignment Pretest
Intervention Posttest
X
O
1
O 2
Figure 5.1g. Two-group posttest-only design without random assignment: Static
group comparison.
son, improves on the one-shot ex post facto design by adding an untreated
control group—an independent case that is evaluated only at time 2. The relation
between smoking cigarettes (the intervention) and getting lung cancer (the
dependent variable) is easily seen by applying the humble ex post facto design
with a control group for a second posttest.
In 1965, when the American Cancer Society did its first big Cancer Preven-