Nice info on the basics of ROI from a training perspective. As Marc says though, the problem we often encounter is the environment or organisation itself. These ROIs typically take longer to plan and execute than the solution would by itself, which normally leads to a lot of resistance. Added to this, the external factors involved are often near impossible to exclude from the analysis which can be tricky.
The key in my experience is the role we as IDs/training teams/training departments play in the process of 'performance improvement'. Are we just order takers, are we ticking boxes or are we trusted advisors?
I'm sure you would be hard pressed to find anyone in these parts that would argue the fact that training (in its various guises) adds significant value to the performance of the organisation, if designed, developed and implemented properly. The question is how do we change the way we are seen and make our value-add clear enough prior to the ROI so that we have the necessary traction to perform a proper ROI (it's a bit chicken and egg) and reinforce the value we know to be there.
I would love to hear about experiences others have had in the achievement of this.