Elon Musk’s Department of Government Efficiency has repeatedly posted error-filled data that inflated its success at saving taxpayer money. But after a series of news reports called out those mistakes, the group changed its tactics.

It began making its new mistakes harder to find, leaving its already secretive activities even less transparent than before.

Mr. Musk’s group posted a new set of claims to its website on March 2, saying it had saved taxpayers $10 billion by terminating 3,489 federal grants.

Previously when it posted new claims, DOGE, Mr. Musk’s government-restructuring effort, had included identifying details about the cuts it took credit for. That allowed the public to fact-check its work by comparing its figures with federal spending databases and talking to the groups whose funding had been cut.

This time, it did not include those details. A White House official said that was done for security purposes.

The result was that the group’s new claims appeared impossible to check.

The New York Times, at first, found a way around the group’s obfuscation. That is because Mr. Musk’s group had briefly embedded the federal identification numbers of these grants in the publicly available source code. The Times used those numbers to match DOGE’s claims with reality, and to discover that they contained the same kind of errors that it had made in the past.