This is a powerful aspect of IDA. By including these correlated influences, we can attempt to explain why study differences are present within IDA findings. For example, we may find that once we control for SES, study differences on our depression outcome are significantly diminished. Without this information, we are in the same situation as other methods of study integration, such as literature reviews, in which we can only speculate as to the reason for study differences in a pattern of findings. Such speculations often form the basis for a new line of inquiry and require additional data collection. However, if we include these variables in our IDA, we can directly test these speculations at the point of initial study integration, bypassing the need for a new data collection to resolve anticipated study differences.
