Have you seen the movie Alien versus Predator? The Predators and Aliens built a sci-fi-like city under the Pyramids, where they hunted, hid and killed each other.
If at all real, the sci-fi city reminds me about how the "ROI" school of thought wants us to believe that "ROI" is the 5th layer in Kirkpatrick's 4 Levels of Assessment.
Kirkpatrick says, the 4th level is measuring training results. Confusing training results with the data gathering process of ROI is dangerous.
We should keep it simple.
Focus on results - NOT the activity of ROI.