"The history of thought about how errors happen is not something I can engage in, because from the initial fact to what the president said, I don't know the whole chain of command," Hassett said.
"I'm not the chairman of the council of Twitter advisers," he added later.
On Monday morning, Trump tweeted that “The GDP Rate (4.2%) is higher than the Unemployment Rate (3.9%) for the first time in over 100 years!”
The Washington Post, Fox News, Bloomberg News and several other news organizations published reports finding that the tweet was untrue. Such a relationship between GDP and the unemployment rate has occurred many times, most recently in the first quarter of 2006, before the financial crisis pushed the unemployment rate high and economic growth slowed markedly.
It also wasn’t clear why Trump focused on those numbers. Economists do not usually compare the GDP rate, which measures the pace of economic growth, with the unemployment rate in that way.
Hassett said the statement the president should have made is that the GDP rate rising above the unemployment rate had not happened in 10 years. Hassett said the “100 years” statement was a mistake he could not explain.
"What is true is that it's the highest in 10 years, and at some point somebody probably conveyed it to him adding a zero to that, and they shouldn't have done that," Hassett said. "You'd have to talk to the president about where the number came from, but the correct number is 10 years."
Hassett’s press briefing was largely supportive of Trump’s record on the economy, and the comments about the erroneous Twitter post came in response to a question from a reporter.
Trump at times boasts about economic news that he sees on Fox News in the morning, but Fox was one of the news organizations that noted the Twitter post was wrong.
Top advisers usually fervently defend the president when he is accused of spreading false information.
This wasn’t the first time Hassett has weighed in on a presidential tweet. Several months ago, Trump broke precedent by issuing a Twitter post that appeared to tout government data that had not yet been released. Administration officials have historically avoided commenting on such sensitive information before it has been released to the public.
At a Washington Post event a few weeks later, Hassett said it was “probably best” for the president not to tweet before such data is announced.