How to include historic versions of org tree in OTBI workforce trend analysis?

Summary

Analysis containing HC summaries spanning years does not accurately reflect earlier org tree versions

Content

Subject Areas:

• Workforce Management - Workforce Trend Real Time
• Workforce Management - Worker Assignment Event Real Time

I've built a very simple analysis showing head count values by month, quarter, and year. I use this as a foundational step to calculate average HC when deriving other standard metrics (attrition, growth, promotions, transfers, talent mobility, etc). When I add in the fields for department and division (org hierarchy level 1), I've noticed that any departments which have shifted from one division to another always appear in their current division.