President Donald Trump on Tuesday said his administration has created “over 600,000 jobs” since he took office. But that’s a lot more than the government’s own scoresheet says.

At first glance, Trump is not far off. The U.S. economy added 533,000 new jobs in the first three months of the year, according to the official survey of business establishments the Labor Department has been conducting for decades.

Yet even that overstates the number of jobs created during Trump’s tenure. Here’s why.

For one thing, former President Barack Obama didn’t leave office until Jan. 20, when two-thirds of the month was over.

What’s more, the survey used by the government to calculate job creation always occurs in the middle of the month. In other words, companies were asked about how many new jobs they created in January before Trump took office.

As a result, economists generally credit hiring in January during a White House transition to the outgoing president.

Subtracting the 216,000 jobs created in January from Trump’s tally leaves his official count at 317,000 — about half of what he claims.

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Even if Trump were generously credited with one-third of the new jobs created in January, his total would be less than 400,000.

A White House spokeswoman said the president was taking note of “the growing optimism about his policies and the future outlook of the country.”

“We seen hundreds of thousands of jobs created and the unemployment rate drop to a 10-year low, historic levels of economic confidence from consumers, to CEOs to small business owners, a stock market hitting record highs, and the trade deficit falling as exports grow,” the spokeswoman said.

To be fair, employment does look better early on in the Trump administration via other, less reliable measures.

A separate government survey of U.S. households, for example, shows an additional 919,000 people said they were working in March compared to January. And a report by the giant payroll processor ADP found that private-sector employment climbed by 508,000 in February and March.

Neither report is seen as credible as the so-called establishment survey, however.

The idea of attributing job creation to presidents, of course, is ultimately a fool’s errand even though it’a time-honored tradition for administrations to take credit in good times. Presidents don’t directly create jobs unless they hire more government workers.

At best presidents can create conditions that lead to more hiring.

Trump is pushing for a set of pro-business policies that largely meet with approval of big and small companies alike. Some have promised Trump publicly to hire thousands of workers, but many of those plans were either previously announced or were already in the works.

Even if more companies announce big hiring plans, such promises won’t be easy to fulfill. After years of steady job creation that’s pulled the unemployment rate down to 4.5%, economists say it will be hard for Trump to achieve his goal of even faster hiring. Already there are widespread complaints by companies that they cannot find enough skilled workers to fill open positions.

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There is a “mismatch between the skills that unemployed have and the skills that businesses are looking for,” said Gus Faucher, chief economist at PNC Financial Services.