Total Actual Effort in Learning by Department

Summary:

I am trying to write an OTBI analysis where we are able to pull in the total headcount of a department, the total actual effort hours of learning for that department, to then be able to work out the average hours of learning per department.

Content (required):

I have 2 problems I'm encountering:

I can acheive actual hours per department by using: SUM("Completion Information"."Total Actual Effort" by "- General Information"."Department Name")  from Learning Records subject area.

But I can't seem to combine in Headcount from Assignment real time subject area. Assignemtn count gives me the same number across all departments, Headcount gives me a hugely inflated number.