The opportunity cost of an intervention includes financial cost and time spent on other beneficial activities.

“the other thing you have to keep in mind is their prescription for use was two 20-minute sessions a day uh much along the lines of um like transcendental meditation which is uh similar but has much better data and that's where i i kind of thought well there's a problem because for most people who are super busy 40 minutes a day for very questionable benefit didn't make a lot of sense if it came at the expense of other things that undoubtedly had benefit such as could that be 40 minutes a day of actual meditation could that be 40 additional minutes a day of sleep could that be 40 minutes a day of exercise”