That is a new paper by Casey Mulligan, here is the abstract:
The Affordable Care Act includes four significant, permanent, implicit unemployment assistance programs, plus various implicit subsidies for underemployment. Every sector of the economy, and about half of nonelderly adults, is directly affected by at least one of those provisions. This paper calculates the ACA’s impact on the average reward to working among nonelderly household heads and spouses. The law increases marginal tax rates by an average of five percentage points (of employee compensation), on top of the marginal tax rates that were already present before the it went into effect. The ACA’s addition to labor tax wedges is roughly equivalent to doubling both employer and employee payroll tax rates for half of the population.