Did the authors measure any mediating explanatory factors or theoretical variables?
That is, did the authors measure any theoretical variables that were proposed to contribute to the problem, and which the intervention aimed to change?
What precipitating (triggers of the problem) and/or perpetuating factors (sustaining the problem) are addressed by the intervention?
What theory and research is the intervention based on?
Does the intervention draw on existing interventions that address the same or similar factors?
What was the intervention hypothesis?