The fi ve research strategies are summarized in Table 6.3. For organizational
purposes we group the fi ve research strategies into three broad categories:
1. Strategies that examine individual variables instead of relationships
between variables.
2. Strategies that examine relationships between variables by measuring
two (or more) variables for each participant.
3. Strategies that examine relationships between variables by comparing
two (or more) groups of scores.
Note that the three research strategies in Category 3 form a hierarchy in
terms of their ability or interest in explaining relationships between variables.
Experiments are designed to demonstrate cause-and-effect relationships. That
is, experimental studies produce unambiguous explanations by demonstrating
that changes in one variable are responsible for causing changes to occur in a
second variable. Quasi-experimental studies would like to demonstrate causeand-
effect relationships but fall short of achieving this goal. Finally, nonexperimental
research simply attempts to demonstrate that a relationship exists, and
makes no attempt to explain why the two variables are related. Also notice that
although the correlational and nonexperimental strategies use different data,
they have the same purpose and produce the same kind of conclusion.
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