Have 1.6 million undocumented immigrants left the U.S. this year? Researchers say it’s too soon to know.

Homeland Security Secretary Kristi Noem said last week that the number of unauthorized immigrants living in the U.S. has declined by 1.6 million since President Trump began his immigration crackdown. 

“This is massive,” Noem said in a statement, crediting the decline in part to an ad campaign warning undocumented immigrants to leave or face arrest and deportation. 

“This new data shows illegal aliens are hearing our message,” she added. In the Department of Homeland Security’s news release, Noem did not specify how many of those individuals were believed to have departed the U.S. voluntarily, versus those who have been deported. 

But the vast majority would have had to have left without making any contact with DHS to reach that total. According to internal government figures previously obtained by CBS News, over the first six months of President Trump’s second term, the administration deported nearly 150,000 people and recorded 13,000 who self-deported. 

A DHS spokesperson told CBS News that it sourced the 1.6 million figure from its own numbers out of U.S. Citizenship and Immigration Services, although its news release included a chart from an analysis released earlier this month by the Center for Immigration Studies, a group that supports immigration restrictions. 

It did not provide additional information on how USCIS calculated this estimate. 

Any estimate of the current unauthorized population at this stage comes with caveats, researchers who study population demographics told CBS News, and it’s too early to conclude that there’s been a mass exodus. 

A new analysis from the Pew Research Center, released Thursday, estimated that there were 14 million unauthorized immigrants living in the U.S. as of 2023. That’s the latest year for which data from the Census Bureau’s American Community Survey is available — the survey that experts say is the gold standard for making these population estimates. 

The Pew Research Center’s analysis found that the undocumented immigrant population swelled by 3.5 million from 2021 to 2023, driven largely by recent arrivals during the Biden administration. 

It had previously declined by 1.1 million between the start of the Obama administration and the end of the first Trump administration, Pew found. 

Meanwhile, the analysis from the Center for Immigration Studies is based on another Census Bureau survey known as the Current Population Survey. The CPS polls about 60,000 households — about 2%…