Multi-variate Analysis - the examination of relationships between
three or more variables.
The elaboration model helps us to better understand and interpret the explanatory or causal implications of relationships between two variables though the introduction of control variables.
Control variables - variables other than the independent or dependent variable which are introduced into multivariate analysis in order to test for spuriousness.
Possible results of the elaboration process:
1. Replication - the original relationship stays the same.
2. Explanation - the original relationship is explained away as spurious.
3. Interpretation ("reinterpretation" in the text) - our understanding of the original relationship is strengthened.
4. Specification - the conditions under which the original relationship exists are clarified.
Three-way crosstabulation - a type of multi-variate analysis which permits the introduction of a control variable into a crosstabulation of an independent and dependent variable.
Three-way crosstabulations are best understood when interpreted in the context of the original two-way relationship which they are meant to test. For example, this is the result of the crosstab of actual weight loss by participation in a weight loss program:
The results of a three-way crosstabulation may be presented in two tables, as:
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If either the independent or control variables is dichotomous, the same results can be presented in one table omitting the cell percents of one of the values of that variable since they are redundant.
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