Chris Conover shares with Forbes readers important data detailing the Affordable Care Act’s impact on the affordability of health insurance.

When the Society of Actuaries estimated spring 2013 that the ACA would result in increasing claims costs by an average of 32 percent nationally by 2017, such estimates could be dismissed as “projections” since at the time of this study, actual premiums in the Exchanges had not yet been announced. A subsequent plethora of studies showed there had been double-digit increases in premiums (when comparing actual Exchange premiums to previously-prevailing premiums in the non-group market). However, virtually all of these studies focused only on Exchange premiums rather than premiums in the entire non-group market (only half of which consists of Exchange coverage). As a consequence, Obamacare proponents tended to dismiss these studies either as partisan attacks or methodologically limited, making what amounts to apples-to-oranges comparisons.

However, a new study from the well-respected and non-partisan National Bureau of Economic Research (and published by Brookings Institution), overcomes the limitations of these prior studies by examining what happened to premiums in the entire non-group market. The bottom line? In 2014, premiums in the non-group market grew by 24.4% compared to what they would have been without Obamacare. Of equal importance, this careful state-by-state assessment showed that premiums rose in all but 6 states (including Washington DC). …

… [U]nlike prior studies which simply compared pre-Obamacare premiums in 2013 to actual premiums offered on Exchanges in 2014, this new study isolates the causal impact of Obamacare statistically by using trend data in each state to figure out what non-group premiums in 2014 would have been in the absence of Obamacare. Thus, critics could dismiss many other so-called “pre-/post” studies by effectively saying “Well, premiums in the non-group have always gone up by a large amount, so what’s happening under Obamacare is no different.” Such criticisms cannot be levied at this study. All of the percentage changes shown in the chart below represent the net change attributable to Obamacare after accounting for all the other factors that would have made premiums go up.

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