For many Americans, a regular 9-to-5 job is an increasingly unattainable achievement.

At least 17 percent of the U.S. workforce is coping with an unstable schedule, ranging from irregular or on-call hours to rotating shifts, that adds stress and leads to unpredictable earnings, according to a study published by the left-leaning think tank Economic Policy Institute. Workers caught in cycles of unstable work schedules are more likely to report conflict between work and family lives, the study found.

Retail companies and those that employ low-wage workers are increasingly turning to sophisticated scheduling software that allows them to change work schedules at the last minute, depending on staffing needs. While that helps corporations cut costs, it's also led to havoc on the lives of employees, who don't know how many hours they'll work or when, making it difficult to plan financially as well as for childcare or social events.

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At the same time, the recession and the post-recovery years has posed challenges to Americans looking for full-time work, with about 6.9 million workers stuck in part-time jobs due to economic reasons. That's still far above the pre-recession number of 4 million Americans in part-time work because of economic reasons, the study noted. Added together, the trends are creating a culture of underemployment, where workers can't predict their earnings or hours, creating stress and also holding back economic growth.

Certain types of workers suffer from unpredictable hours more than others, the study noted. Almost one in three employees in the retail sector report irregular hours, while four in 10 agricultural employees have unstable hours. In the food services or production field, such as fast-food workers, one in five workers have irregular schedules.

Workers who make less than $22,500 annually are more likely to suffer from unpredictable hours than those who earn more.

Starbucks (SBUX) recently came under fire after The New York Times profiled barista and single mother Jannette Navarro, whose life had become a "chronic crisis" due to her fluctuating hours and $9 per hour pay. Her employer used software to create a jigsaw of a puzzle, requiring her to work until 11 p.m. on one night and show up the next morning at 4 a.m.

In response to the article, Starbucks last year vowed to change its scheduling practices to give its workers more consistency.

There may be financial pressure on companies to increase their use of scheduling software rather than decrease it, however. With low-wage employers like McDonald's (MCD) and Walmart (WMT) pledging to raise hourly rates for their lowest-paid workers, restaurants are turning to technology to help minimize their costs, according to the Nation's Restaurant News. One of those tools is scheduling software.

Lawmakers and policy experts should consider regulations to reduce some of the current practices, the report noted. Retail chain stores in San Francisco, for example, are required to provide more advance notice in setting and changing work schedules, providing a more predictable routine for workers.