At a high level, it is easy to describe ROI – the return on the investment. But how do we measure the investment? There’s a problem when we have to go to the next level. Some costs are obviously incurred as part of our actions, and some costs happen even if we don’t take the action. We have to allocate those costs across all our actions or we won’t have an accurate reflection of our investment. Without an accurate model of our investment, we can’t calculate the return on our investment.