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Making Sense of the
Social World
th
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Chapter 6, Causation and Experimental Design
Five criteria should be considered when trying to
establish a causal relationship.
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Empirical association
Temporal priority of the independent variable
Nonspuriousness
Identifying a causal mechanism
Specifying the context in which the effect
occurs
Chambliss/Schutt, Making Sense of the Social World 4th edition
© 2012 SAGE Publications
Empirical Association
The independent variable and the dependent variable must vary together.
A change in X is associated with a change in Y.
ΔX
ΔY
Chambliss/Schutt, Making Sense of the Social World 4th edition
© 2012 SAGE Publications
Temporal Priority of the Independent Variable
The change in X must occur before the change in Y.
ΔX
t1
ΔY
t2
Chambliss/Schutt, Making Sense of the Social World 4th edition
© 2012 SAGE Publications
Nonspuriousness
We say that a relationship between two variables is spurious when it is
due to variation in a third variable; so what appears to be a direct
connection is in fact not.
ΔX
X
ΔZ
Chambliss/Schutt, Making Sense of the Social World 4th edition
© 2012 SAGE Publications
ΔY
A Causal Mechanism
A causal mechanism is the process that creates
the connection between variation in an
independent variable and the variation in the
dependent variable it is hypothesized to cause.
Chambliss/Schutt, Making Sense of the Social World 4th edition
© 2012 SAGE Publications
The Context in Which the Effect Occurs
No cause has its effect apart from some larger
context involving other variables. When, for
whom, and in what conditions does this effect
occur? A cause is really one among a set of
interrelated factors required for the effect.
Chambliss/Schutt, Making Sense of the Social World 4th edition
© 2012 SAGE Publications
True Experiments Have at Least Three Features
That Help Us Meet These Criteria
•
Two comparison groups (in the simplest case,
an experimental group and a control group), to
establish association.
•
Variation in the independent variable before
assessment of change in the dependent
variable, to establish time order.
•
Random assignment to the two (or more)
comparison groups, to establish
nonspuriousness.
Chambliss/Schutt, Making Sense of the Social World 4th edition
© 2012 SAGE Publications
Research designs that allow us to establish
these criteria require very careful planning,
implementation, and analysis.
But being able to claim causality
makes all that hard work worth it!
Chambliss/Schutt, Making Sense of the Social World 4th edition
© 2012 SAGE Publications