In the second mini d.MBA episode, we look at two related business concepts: Opportunity Costs and Return on Investment (ROI) If you take a year off from work and do an MBA, this doesn’t just cost you $100k. During that same year, you could be earning your salary. So, your opportunity costs (for that year) are way above $100k. A freelancer that takes on a project with a 50% discounted rate won’t be able to sell that time to a much better paying corporate gig if it shows up at a later point. How can we best decide among different opportunities and their costs? One way is calculating ROI.