The target long used by the Maryland health exchange of how many people would enroll in private policies through its website this year was slashed in half after an error came to light, making the state appear far closer to its goal — but still unlikely to reach it.

A top exchange official said Sunday a mistake in a chart outlining exchange projections made by outside analysts put the number of people likely to sign up for private insurance under the Affordable Care Act at close to 150,000 by the end of open enrollment on March 31.

The new number is 70,000 after it was corrected by the Hilltop Institute at the University of Maryland Baltimore County, a nonpartisan heath research organization that discovered its error weeks ago and sent a letter dated Feb. 21 to Dr. Joshua M. Sharfstein, health secretary and chairman of the exchange board.

It was a footnote to one chart that wrongly also included open enrollment targets beginning next fall for 2015 coverage.

"It's always better to have the numbers the experts intended because it provides better context on the progress we've made," Sharfstein said. "This doesn't change any of the challenges we are facing."

The exchange website crashed the day it launched Oct. 1 and has been beset with technical problems since. Thousands of applications have been lost or frozen in the system and others were given inflated subsidy estimates.

Data released Friday shows that just more than 33,000 people have enrolled in private plans so far on the exchange website. With an average enrollment of about 2,000 a week, the exchange will still not meet the lower target without a surge in applicants in coming weeks — something Sharfstein doesn't discount.

The revised projections, which will be presented to a legislative panel today, were already drawing criticism Sunday.

Del. Kathy Szeliga, a Republican party leader and a member of the appropriations committee, said the new projections don't mean the state has helped any more people get health insurance.

"We're still far short of the goal," Szeliga said. "Now, instead of someone stepping up and taking responsibility or taking a leadership position, we have more broken promises. They're spinning it."

Szeliga is sponsoring a bill calling for an investigation of what went wrong.

Sharfstein has begun providing regular updates to lawmakers and said there will be more information provided during today's hearing about where the exchange is with regard to a decision as to whether to fix or abandon the website. He also said Hilltop will offer another set of projections in coming weeks.

Hilltop uses federal income and population data to make projections and can't account for technical problems, said Cynthia Woodcock, Hilltop's executive director.

Woodcock said the error was caught when analysts were beginning to update the projections, after a request from exchange officials. She said the new number, and the old number, only included people obtaining new insurance policies.

But the new target Hilltop provided also includes for the first time an estimate of people who already had policies when they sought new deals on the exchange website.

Woodcock said the number was tough to estimate with limited state and national data, but analysts put it between 5,000 and 30,000, raising the total estimate of those projected to buy private plans during this open enrollment at between 75,000 to 100,000.

Medicaid targets were not altered as much with this correction because the time frame wasn't as off. An estimated 90,000 people were expected to enroll in the state-federal program for the poor, down from 101,000. Already, more than 150,000 have enrolled, including tens of thousands who were automatically moved from a bare-bones state program.

meredith.cohn@baltsun.com