Congressional Budget Office analysts are going on the assumption that only about 20% of preventive health care services save much money.

CBO Director Douglas Elmendorf discusses the return-on-wellness-investment issue in a letter prepared in response to questions from Rep. Nathan Deal, R-Ga., the highest-ranking Republican on the House Energy and Commerce Committee’s health subcommittee.

Early research has suggested that about 20% of preventive care and wellness measures save substantial amounts of money; 60% have costs that are reasonable relative to the benefits; almost 20% have costs that outweigh the apparent value; and a few harm users’ health while increasing overall health care costs, Elmendorf writes.

“In sum, expanded governmental support for preventive medical care would probably improve people’s health but would not generally reduce total spending on health care,” Elmendorf writes.

The CBO sometimes includes the likely benefits of preventive health care measures in budget analyses, but congressional scorekeeping rules can interfere with that, Elmendorf notes.

The scorekeeping rules discourage “situations in which hoped-for, but quite uncertain, savings are used to offset near-term, certain spending increases or revenue decreases in the same legislation, Elmendorf writes.

A copy of the CBO analysis of preventive care and wellness services is available here.