Unpredictable hours, or "just-in-time" employment, is the reality for many working class and middle class Americans. A new study from the Brookings Institute shows it's particularly prevalent among Millennials. The study, which talked to 26 to 32-year-olds, found that 41% of hourly workers learn their work schedule only a few days in advance. Half of those surveyed also reported large swings in their weekly hours, with 10-hour weeks following 30-hour weeks. Fluctuations in hours is prevalent in the fast food and retail industries. 

"[My hours] change from week-to-week, day-to-day, sometimes even hour-to-hour," Jemere Calhoun, a McDonald's employee, told attn. "You could be off one day, and then they call you and say they need you to come in. "

What is the effect of unpredictable hours?

Unpredictable schedules make routine tasks difficult for hourly wage workers. As Calhoun described, he's often triaging his bills -- paying off the most important item as soon as gets paid because he has no idea what his hours will be the following week. A financial plan can only go as far as a few days into the future. This lifestyle takes its toll on workers and their families. Unpredictable hours "exacerbate stress, harm health, and propagate damaging work-life conflicts," according to a similar study mentioned by Brookings.

It can also affect social mobility. Take the story of Janette Navarro, 22, who was profiled by the New York Times. Navarro's plans for a college degree stalled because she was unable to commit to classes due to the unpredictable hours she was getting as a barista at Starbucks. Navarro was stuck. She couldn't finish her degree to get a better job because her current job, which she needed to support her daughter, had unpredictable hours.

Why are so many employees dealing with unpredictable hours?

It has a lot to do with big data. Fast food chains and retailers now rely on advanced software that synchronizes employee hours and company needs. As the New York Times explained, software such as Kronos allows stores to quickly respond to the ups and downs of a business. Will there be a dip in foot traffic because a storm is coming, thus requiring less workers? Or maybe a large shipment is arriving that will require more help? According to the Times, store managers are often compensated for the efficiency of their hourly staffing.

Is there a solution?

While "just-in-time" employment is good for stores and probably good for customers, it leads to turmoil in workers' lives. So what can be done? 

In Vermont and San Francisco, employees have the right to request more flexible schedules so they can take care of children or an elderly parent. In Seattle, voters passed a referendum barring businesses from adding additional part-time workers if there are current staff members who want more hours. 

There are also a few interesting proposals floating around the states. In California, there is a proposal that would require employers to pay for an extra hour of work to employees who are asked to come in with less than 24-hours notice. Another proposal there would guarantee workers receive four hours worth of pay when they are sent home early. 

On the other side, industry groups say that these types of laws are essentially requiring businesses to be inefficient.

Technology has different effects on blue collar and white collar workers 

As was pointed out in the New York Times profile, unpredictable hours are another example of the varying effects of technology. White collar workers, due to their mobile devices and cloud computing, can increasingly work from wherever they want. Technology can be a godsend to working parents who want to be home with their children. But at the bottom of the economic ladder, parents with hourly employment are tied to the whims of workplace optimization software, making it difficult to take care of a family or pursue higher education that might increase the household's income.