WASHINGTON, DC—A recent shift in some key sectors of the economy "has led to millions [of] workers [only] working part-time hours" when they'd prefer to be working full-time, according to the Economic Policy Institute (EPI).

"Part-time workers face shortages of pay and work hours and deserve policy remedies for their problems," said EPI President Lawrence Mishel. "They are a sizable and growing share of the workforce [and] policymakers need to address their problems."

Lonnie Golden, a Penn State professor and University of Illinois Project for Middle Class Renewal analyst, wrote a 59-page paper titled: "Still falling short on hours and pay: Part-time work becoming new normal."

The economics professor who studies part-time work says he often hears people say that they’re “hired with the assumption, if not promise, that they’ll get full-time hours, [but] most weeks they don’t.”

Golden explained that the end of the Great Recession, brought "a structural shift concentrated in a few key industries" that may be to blame for the new dynamic.

And in his research, he points out that the number of people working “involuntarily part time” has increased nearly 45% since 2007.

Although a myriad of segments within the labor market have regained full health since the recession, a "chronically higher level of involuntary part-time workers" shows evidence of an incomplete recovery, Golden found.

“The increase is almost entirely due to the inability of workers to find full-time jobs, leaving many workers to take or keep lower-paying jobs with less consistent hours to make ends meet,” said Golden. “In several industries, relying more on part-time work seems to have become the 'new normal.'”

While most industries do employ part-time workers, Golden notes that between the beginning 2007 recession and 2015, the retail and leisure/hospitality industries accounted for more than 54% of involuntary part-time employment.

“Black and Hispanic workers have been relatively more affected by this structural shift,” says the release, noting that while nearly 4% of whites work part-time "involuntarily," 6.8% of Hispanic workers and 6.3% of black workers find themselves in the same situation.

In comparison to "similar full-time workers" the EPI cites other research showing men working part time earn 19% less per hour, while women working part time earn 9% less per hour.

Aside from not being able to secure more hours most of the time, “part-time workers must also navigate unpredictable and/or variable hours, with their work schedules varying from week-to-week at a rate more than double that of full-time workers,” says the release.

Part-time workers are usually paid less and may not have benefits, according to the EPI, which notes that health insurance among part-time workers is virtually nonexistent.

But Golden did not find the fulfillment of the “employer mandate” in the Affordable Care Act, which required all businesses with at least 50 full-time employees to provide health coverage to most of their full-time employees and dependents up to age 26, or pay a fee, to cause the rise in involuntary part-time work.

Data did not reflect much of a jump in involuntary part-time or workers working 29 or fewer hours a week around the time the mandate was put into place.

While there's been a structural shift toward involuntary part-time labor, Golden says it should be addressed with specific policy solutions that will help workers.

Golden feels that policies like the “Opportunity to Work” ballot measure which was passed in San Jose, California and secure scheduling provisions like the ones in Seattle, Washington could be put into practice across the country.

“These include compensation parity for part-time jobs, reforms to unemployment insurance systems, an employee 'right to request' changes in hours and schedules, and laws giving part-time workers priority access to increased hours when available,” says the EPI, citing Golden's research.

“We should use every tool in our toolbox to further the economic recovery and help benefit millions of workers with more stable, better-paying job opportunities,” he added.