The intent of the stimulus program was to pump money into the economy quickly, and many members of Congress said at the time of its passage that speed was of the essence. But the huge program has been a challenge to administer for both a new administration and for states and local governments grappling with their own fiscal problems.

Some states and cities are beginning to complain that the money has yet to reach them. Others have been slow to get their paperwork to Washington; Virginia has yet to send the Transportation Department its list of road projects.

At the same time, some economists have questioned the administration’s claims that the bill has saved or created 150,000 jobs.

Obama administration officials, however, say the pace of the stimulus program is on schedule, and even if the federal checks are not yet in the mail the effects of the stimulus are beginning to reverberate: the promise of the federal money has been enough to get states to start construction work and to retain some jobs that were in jeopardy.

Vice President Joseph R. Biden Jr., who writes in a report on the stimulus bill to be released this week that it remains “ahead of schedule in most programs,” said in a telephone interview Tuesday that the bill was helping people grapple with the recession, getting money to the states and into the economy, and laying a foundation for long-term aspirations like high-speed rail.