# Is it appropriate to include overlapping sub-scale scores and total-scale scores in a meta-analysis?

## Question, brief

In a single multi-level meta-analysis, is it appropriate to include subscale scores (which represent part of a measure) in addition to total scale scores (representing the full measure), all nested under study?

## Question, detailed

I am conducting a meta-analysis on the correlation between two constructs. One of these constructs is frequently measured using a questionnaire that consists of two subscales.

To make this clearer, let's say Measure A is my measure of Construct 1. Measure A contains Subscale 1 and Subscale 2. For some studies, I have the correlation between the total score, as well as both subscale scores, and Measure B (which measures Construct 2). For some studies, I only have the correlation between Measure A (total) and Measure B. For some studies, I only have the correlation between a subscale score and Measure B.

Measurement of Construct 1 in each study (I have the correlation of each of these scores with my measure of Construct 2 (Measure B)):

• Study 1: MeasureA-Total, MeasureA-Subscale1, MeasureA-Subscale2
• Study 2: MeasureA-Total
• Study 3: MeasureA-Subscale1, MeasureA-Subscale2
• Study 4: MeasureA-Subscale1
• Study 5: MeasureA-Subscale2
• Study 6: MeasureA-Total, MeasureA-Subscale1
• Study 7: MeasureA-Total, MeasureA-Subscale2

Would it be appropriate, statistically speaking, in the case of study 1, to include the correlation of each form of Measure A with Measure B in my analysis (three different correlations)? Because Measure A, Subscale 1 makes up part of the Measure A total score, there is dependency between these scores. However, it seems to me that my multi-level analysis should account for this dependency.

I would like to include both the correlations involving the total score and the subscale scores to maximize the number of effect sizes I am including in my analysis. I would like to test each subscale as a moderator, and if I do not include the effect sizes involving the subscales scores in my initial analysis, this test of moderation would not include as many effects as it might otherwise.

The other option I can see would be for me to use the total scale score, when available, and use the subscale score(s) when the total scale score is not available.