The information you request has to be detailed enough so that an experienced member of the department can understand and act on it.
When I teach access to information, I inform students what is required. I tell them not to play cat and mouse, say exactly what their after and then put in a request. Put a background on it: “Once upon a time, there was a study. I'm interested in this.” Then there's no hesitation as to what records you're after.
A skilled requester will know how to get those records. Info Source, which is produced by Treasury Board on a yearly basis, provides a mountain of information on programs and so on so that you as a requester can inform yourself and can have a deliberate explanation to what you were after.