The CBO said that over 10 years the health care law was likely to reduce compensation nationally by 1 percentage point. That's a "proportionally smaller" effect than the fall in hours worked.
The impact on hours worked is likely to come further out in the decade, and in the near term the health care revamp will be a "boost to demand for goods and services," CBO Director Douglas Elmendorf said. That translates into more jobs, though neither he nor the White House could say how many.
The subsidies for health insurance "will both stimulate demand for health care services and allow low-income households to redirect some of the funds that they would have spent on that care toward the purchase of other goods and services — thereby increasing overall demand," the CBO report said. "That increase in overall demand while the economy remains somewhat weak will induce some employers to hire more workers or increase the hours of current employees during that period."
Poor and middle-income workers have a greater propensity to spend, with economic research showing that these groups save very little.
The estimated effects of the Affordable Care Act on employment are an update on a 2011 report in which the CBO calculated that workers would put in reduced hours that added up to the equivalent of 800,000 jobs. The changes reflect more information obtained as the law is being implemented. A better read on the impact of the massive health care revamp is likely to come around 2016, Elmendorf said.
The updated estimates "would not reverse the original conclusion" by the CBO that repealing the health care law would make deficits worse over the next 10 years, Elmendorf said.
Also, the CBO expects 1 million fewer people than once predicted — 6 million — to gain coverage through marketplaces this year, because of major technical problems with the October debut of the federal website HealthCare.gov.
The number of people likely to be insured through the Affordable Care Act's Medicaid expansion likewise has been downsized, from 9 million to 8 million this year.
About 5 million people are expected to receive subsidies to help purchase marketplace coverage this year, rising to nearly 19 million in 2016.
The CBO estimates that subsidies will cost $15 billion this year, rising to $143 billion by 2024.
The CBO also said it projected a federal budget deficit of $514 billion for fiscal 2014, after a peak of $1.4 trillion in fiscal 2009.
David Lightman contributed to this article.