Nick Rowe, Professor of Economics at Carleton University, takes real option theory to task at the Worthwhile Canadian Initiative blog. Rowe says that real option theory includes the option of doing nothing as one of its "neatest options." But this option overlooks the idea that doing nothing is indeed doing something--especially when cash is involved.

You can't just do nothing with your income; you have to spend it on something. If all things you could spend it on were irreversible, then you can't talk about the option value of doing nothing, or postponing a decision. You have to decide now. You could insulate your house with R20, or buy a new car, or buy a holiday, but none of those expenditures is fully reversible. You can't return the holiday after you have enjoyed it; you can't re-sell the new car and get anything like what you paid for it.

There is one thing you can spend your income on that is very reversible: cash. In fact, if we spend our income on cash, we don't even think of that as spending it at all. We think of that as not spending it. We think of holding cash as doing nothing. In fact, since we live in a monetary exchange economy, our income comes to us as cash anyway. So it's not like we make a decision to invest in cash today, and then reverse that decision next year. We have the cash already, and can decide to spend it now, or decide later to spend it later. Holding cash keeps our options open. Cash is the real real option -- to do anything.

Talking about the option value of doing nothing only makes sense in a cash economy. If we invest in insulation we cannot reverse that decision next year. If we hold cash, we can reverse that decision next year. Holding cash is to hold the option. Holding insulation is to exercise that option, so you no longer hold the option.

Read Cash as the real real option -- to do anything here.