Seniors seem to like the new Medicare drug program, but they may not understand it very well.

Researchers at DSS Research Inc., Fort Worth, Texas, have published data hinting at those conclusions in a report on results of a quarterly survey of U.S. seniors conducted in mid-April. The firm conducted a similar survey in mid-December.

Federal officials say 38 million U.S. residents, or 90% of the Medicare beneficiaries eligible for the Part D prescription program, enrolled in the program by May 15.

About 78% of the participants said they definitely or very likely will renew Part D coverage with their current carrier, and 72% said they are completely or very satisfied with the ease of filling prescriptions under their Part D plan, according to DSS researchers.

But only 58% felt that the carrier enrollment materials were extremely or very clear, and only 57% said they understand their plans benefits extremely or very well, the researchers report.