Supporters of the law say these reforms will unleash a wave of entrepreneurship as workers find it easier to obtain health insurance.
But opponents argue the law's most popular provisions come with downsides, even if they ease the plight of a few entrepreneurs.
Critics say employers may stop offering health insurance altogether, forcing workers into the exchanges and denying people health coverage they know and like.
Republicans also argue that the law will increase healthcare costs for the government and for families.
Friday's report criticized the status quo in health insurance, saying it encourages "job lock," when workers are wary of starting their own ventures because non-group coverage is unpredictable and expensive.
"Afraid that they may be denied health insurance coverage because of pre-existing conditions, unable to affordable the premiums, or lose access to a trusted provider, many workers may decide to stay in their job, even if their skills and talents are not optimally deployed," the study's authors wrote.
The report predicted that Massachusetts and Vermont will not experience bursts of entrepreneurship in 2014 because those states already enacted reforms similar to the federal healthcare law.
California and Texas, on the other hand, will add as many as 248,000 and 124,000 self-employed workers, the Urban Institute said.