President Barack Obama signs PPACA. (AP Photo/J. Scott Applewhite, File)

Policymakers probably won’t know how the Patient Protection and Affordable Care Act of 2010 (PPACA) will really affect job lock until PPACA takes effect.

Andrew Sherrill, a director at the U.S. Government Accountability Office (GAO), gives that assessment in a review of the possible effects of PPACA on job lock, or the tendency of workers — especially workers with health problems, or dependents with health problems — to stay with jobs they would otherwise leave because of a need to keep health benefits.

If PPACA takes effect as written and works as expected, it is supposed to require most large employers to offer health coverage or pay a penalty, and it is supposed to give individual consumers the ability to buy coverage on a guaranteed issue, mostly community-rated basis.

Small businesses are already starting to get PPACA tax credits that are supposed to help them pay for health coverage, and small businesses are supposed to get new coverage tax subsidies starting in 2014.

“The studies we reviewed generally found those workers who rely on their employer-sponsored health benefits are less likely to change jobs, leave the labor market, become self-employed, or retire when eligible, compared to those who have access to alternative sources of coverage,” Sherrill says. “For example, one study found men with employer coverage were about 23% less likely to leave a job compared to those who also had access to coverage through a spouse.”

But there is not much solid information about the relationship between job lock and prevalence of preexisting conditions, and predicting the effect of specific PPACA provisions is difficult, Sherrill says.

The large employer coverage mandate could help, for example, but most large employers already offer coverage, and PPACA could lead some to choose to drop coverage and pay a penalty, Sherrill says.

The small business tax incentives in effect before 2014 could help, but they may not do much, because they are temporary and of limited value, Sherrill says.

The PPACA small business subsidy that is supposed to start in 2014 could help, but how that provision will work is still unclear, Sherrill says. If the subsidy does increase the percentage of small businesses with health coverage, that could reduce job lock, he says.