Negative ads about Obamacare may actually have encouraged some people to sign up. That’s the finding of a study by the Brookings Institution released last week.

Brookings calculated the ratio of enrollees for each state (total number enrolled divided by those eligible) and compared it to spending on negative Obamacare ads in each state. What the comparison found was a slight correlation between the negative ads and increased enrollment.

The impact of the ads was not uniform but varied depending on the state where they were being run. In blue states, the negative ads appeared to have a slight positive impact on enrollment. In red states the ads appeared to depress enrollment by a similar amount.

The total differences in both cases were only a few hundredths of a percent but spread over multiple states, including large ones like California and New York, those differences would add up to tens of thousands of enrollees.

The author of the study speculates, “anti-ACA ads may unintentionally increase the public awareness about theexistence of a governmentally subsidized service and its benefits forthe uninsured.” In other words, calling attention to the law, even in a negative way, may have led to more public awareness about its benefits as well as its downside.