San Francisco has passed a "retail workers' bill of rights" — a package of legislation aimed at improving life for workers in stores and restaurants. The measure addresses a problem less quantifiable than wages: unpredictable scheduling. A recent study found that 41 percent of early-career (26 to 32 years old) hourly workers said they only knew their schedules one week in advance or less.

The "bill of rights" is really two bills

San Francisco is becoming known for its worker-friendly policies, having recently voted to gradually raise its minimum wage — already nearly $3.50 above the federal minimum, at $10.74 per hour — to $15 per hour over three years.

On Tuesday afternoon, San Francisco's Board of Supervisors took another step in that direction, unanimously passing a "retail workers' bill of rights," the first such bill to be passed in a large US city. That "bill" is in fact two pieces of legislation containing five provisions aimed at making life easier for hourly workers at the city's chain restaurants and stores.

Among other things, the bill will require employers to post schedules two or more weeks in advance, give additional hours to part-time employees instead of hiring new workers, and pay employees for any hours they are put "on call," only to have their shifts canceled.

The latest measures are meant to provide protection against unpredictable scheduling, which has become huge problem for low-income workers. Many employers have started using sophisticated "just-in-time" scheduling software, which decides how many workers have to work at a given time based on data points like traffic, sales levels, and even weather, as MSNBC has reported. This type of software has often led to erratic, short shifts for many workers.

Hourly workers increasingly don't know when they'll work

According to one recent University of Chicago study, 41 percent of early-career (26 to 32 years old) hourly workers said they only knew their schedules one week in advance or less. In addition, those hours could swing dramatically: "in the course of a single month, workers' hours varied on average by 37 percent in comparison to what they considered their usual hours."

This of course makes life tougher for workers who have to schedule their work around children and other family members (not to mention juggle two or more jobs), but the problems go beyond scheduling. Unpredictable shifts — and thus, unpredictable income — makes financial planning nearly impossible.

One of the most serious, and least covered, problems low-income Americans face is fluctuations in income. Fully 20 percent of Americans in the bottom quintile of earners experienced an income drop of 50 percent or more within a year, according to a 2010 paper from the Urban Institute.

Workers in San Francisco will now know two weeks ahead of time if this week's 30 hours could become 15 later in the month. That can hurt, but it at least allows a family to better save and plan for lean times ahead.

Bills like this one are partially a response, as Politico's Marianne Levine writes, to the decline of unions in the US. While scheduling and wages were once the province of union-business negotiations, labor's waning power has driven these sorts of fights into the political arena, like City Hall and state houses.

This type of bill has been introduced on the federal level; Democrats in July introduced the Schedules that Work Act, which would have similarly promoted more advance scheduling. That bill is in committee but isn't expected to pass.