Five years ago, about a quarter of all nursing facility residents were receiving rehab care in concurrent therapy sessions. These days, almost none do. But it’s not hard to see why this service option has essentially dried up.

With apologies to the movie “Cool Hand Luke,” what we have here is a failure to remunerate. Prior to the Minimum Data Set 3.0, many therapy departments opted for concurrent treatment instead of group therapy, thanks largely to a 25% allowance calculation. When the government recently opted to cut reimbursement levels here, providers decided to pursue other options.

For those of you unclear on the distinction, group therapy is delivered to residents working on the same core skill. Concurrent therapy, or stacking, happens when residents are not all working on the same skill.

The industry’s collective response will hardly come as surprise to anyone who has studied Economics, or at least skimmed through the book “Freakonomics.”

In the latter, authors Steven D. Levitt and Stephen J. Dubner examine matters such as cheating teachers and sumo wrestlers, crack dealers who live with their mothers — and a possible connection between legal abortions and lower crime rates. In every instance, they point to one of the basic principles of economics: People respond to incentives.

And what Medicare incentive is CMS throwing out these days? The bottom-line answer: Don’t deliver concurrent therapy. Does that mean that we will never again see concurrent therapy delivered in skilled nursing facilities? It depends.

Should it become clear that concurrent therapy results in improved clinical outcomes, a small number of operators will likely embrace it. Their rationale will be that it’s the right thing to do. But to really move the needle, fiscal sweeteners will almost certainly be required. And the last time I checked, CMS was not exactly looking for ways to put more money in providers’ pockets.

Guess there’s no reason to wonder why economics is called the dismal science.