Dozens of federal programs to help Americans with disabilities find jobs are fragmented and overlapping, potentially making services for this vulnerable population inefficient and wasteful, government auditors reported.

Even with at least $4 billion a year allocated by nine federal agencies to employment programs, the government does little to measure whether the efforts are putting the disabled to work, how long those workers stay employed and whether they are satisfied with their jobs, the Government Accountability Office found.

“Many programs have not evaluated their programs for effectiveness, and little is known about effectiveness overall,” GAO auditors concluded in a 91-page report released last week. The result is that “policymakers have limited information to help them make informed decisions on allocating scarce resources.”

The report, “Employment for People With Disabilities,” is one in a series of audits by the congressional watchdog this year that have pointed out duplication and waste in federal programs.

President Obama pledged to reduce this kind of overlap in last year’s State of the Union address. But in an unwieldy bureaucracy, progress can be slow.

According to the Census, nearly one in five people in the United States has a disability. Some are chronic mental or physical conditions, while others are short-term impairments related to employment, illness or aging. Despite a willingness to work, disabled people often have a hard time finding jobs because of inadequate education, skills or training; inaccessible workplaces; transportation barriers; or outright discrimination.

GAO auditors identified 45 federal programs that support employment for the disabled. They are overseen and administered by at least 13 congressional committees and nine executive agencies, as well as state and local offices. Most provide similar services to similar populations.

The Labor Department, for example, runs 14 similar programs, the auditors found. The Defense Department has 10 programs to help ill and injured service members find jobs. The Department of Education gives grants to state agencies, which run their own programs. Few coordinate with each other.

“Fragmented programs that do not coordinate effectively could waste scarce funds, confuse and frustrate program beneficiaries, and limit the overall effectiveness of the federal effort,” the auditors wrote.

With so many different initiatives, it is almost impossible to track how much the government is spending. The 45 programs surveyed spent about $4.1 billion on employment support for at least 1.5 million disabled people in fiscal 2010, “but these numbers may be largely underestimated,” the report found.

Programs with strict limits on whom they serve — veterans with mental illness, for example — tend to be easier to track and are less likely to be duplicated. In contrast are efforts such as three Labor Department programs that are potentially open to any young person with a disability between ages 16 and 21; all three offer job-readiness skills, on-the-job training and help getting a high school diploma.

Labor Department officials told the auditors that despite their similarities, the programs use different approaches, with one focusing more on construction skills and another putting young people to work building affordable housing for homeless and low-income people.Department officials told the auditors that they are developing procedures for consolidating some programs.

Officials at other agencies had varying responses to the GAO report.

The Agriculture Department generally agreed with its conclusions.

Education officials said some of their programs coordinate with states, which provide a wide range of individualized services to the disabled that are not duplicated by other programs.

Labor Department officials called the GAO’s definition of duplication overly broad and said its programs have more differences than the auditors found.