The progress report by the Federal Trade Commission comes more than half a year after the agency concluded that the movie, video game and music businesses were aggressively peddling products that carry adult ratings to children.
The FTC recommended that industry groups and individual companies crack down on the practice themselves. Some lawmakers, irate at the report's findings, threatened government sanctions if the industries couldn't make good on their pledges of self-regulation.
In the follow-up study, expected to be released Tuesday, the commission found that music companies have not made significant progress in stopping such practices, according to sources familiar with the report.
In turn, video game makers and movie studios have had some success in policing themselves, said the sources, speaking on condition of anonymity.
Officials with the Recording Industry Association of America defended their industry in a story in Sunday's Los Angeles Times, which first reported the follow-up study.
"We are the only industry that offers edited versions of our stickered material to consumers," RIAA spokeswoman Amy Weiss told the newspaper. "And we have a system in place that the FTC's own report said 75 percent of parents find useful and effective."
Last fall, much of the scrutiny was focused on movie executives, who were chastised by senators for such practices as showing R-rated movies to focus groups that included children as young as 10. Studios devised voluntary guidelines after the release of the report to curtail underage marketing.
The recording industry, which has a more general label that warns of explicit content in music, also was taken to task by the commission's study: of 55 music recordings with explicit-content labels studied by the FTC, all were targeted to children under 17.
At hearings on Capitol Hill, lawmakers highlighted the graphic nature of lyrics by some artists and Mrs. Cheney, wife of vice president Dick Cheney, took aim at rap star Eminem.
But music industry representatives strongly rejected suggestions that they should go beyond their current rating system.
The report being released this week provides a quick follow-up on the success each industry had in acting on the FTC's recommendations. Its findings could spur to action lawmakers, who already are dissatisfied with the response by entertainment executives.
Sen. Joe Lieberman, D-Conn, an outspoken critic of the industry, said last week he would introduce a bill giving the FTC authority to fine companies that market adult-rated material to minors.
"What we've heard essentially is that the video game industry has done the best job of not marketing adult-rated material to minors, the record industry's done the worst job, and the movie industry's in the middle," said Bill Andresen, Lieberman's chief of staff.
The commission has told Congress that it currently has limited authority to crack down on entertainment companies that engage in such practices.