It’s also unclear from the data what may be behind May’s growth in part-time jobs. The only breakdown the BLS provides is for “economic” and “non-economic” reasons. The agency defines economic reasons as “slack work or unfavorable business conditions, inability to find full-time work, or seasonal declines in demand.” Non-economic reasons have to do with “childcare problems, family or personal obligations, school or training, retirement or Social Security limits on earnings”.

In May, the number of people working part-time for non-economic reasons went up 17% from April. The number of those working part-time due to economic reasons, meanwhile, fell a little more than 2%.

The increase in part-time workers for non-economic reasons may be due to women and other care providers switching from full-time to part-time work to meet family obligations like childcare, said Rhonda Vonshay Sharpe, president of the Women’s Institute for Science, Equity and Race, a non-profit research organization. However, it’s unclear exactly how many people are making this employment choice because the BLS does not provide additional levels of data—such as industry, race, gender, marital, or parental status—in its standard releases.

“This makes it difficult to figure out the causes, consequences, and potential solutions,” said Sharpe.

Correction: An earlier version of this article compared labor data from two different surveys, leading to a mathematical error. In May, the number of people working part-time and full-time grew by 3.8 million, of which about 40% were part-time, according to the Bureau of Labor Statistics’ Household Survey. 

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