Author Lon­nie Gold­en finds that vol­un­tary part-time work has remained more or less sta­ble since 2007, around the start of the reces­sion. But invol­un­tary part-time work has increased by about 18 times the rate of growth of all work, and five times faster than part-time work. Cur­rent­ly, some 6.4 mil­lion Amer­i­cans who want full-time jobs are stuck work­ing part-time hours, accord­ing to Golden.

The recov­ery from the Great Reces­sion has been long, slow and steady. But it has also con­tributed unex­pect­ed­ly to an increase in invol­un­tary part-time work, which needs new reg­u­la­tion to pro­tect work­ers from abuse, accord­ing to a new study released this week by the Eco­nom­ic Pol­i­cy Institute.

“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,” he says. ​“In sev­er­al indus­tries, rely­ing more on part-time work seems to have become the ​‘new normal.’”

Employ­ers often play it cau­tious after a reces­sion, wait­ing to restore full-time jobs and hir­ing more part-timers as their busi­ness­es pick up. But, as Gold­en points out in his study, the reces­sion isn’t respon­si­ble for the rise in invol­un­tary part-time work. Struc­tur­al shifts are almost entire­ly at play in this change in employment.

Gold­en argues that such an expan­sion rep­re­sents a change in the long-term strat­e­gy of busi­ness­es in four key sec­tors of the econ­o­my, specif­i­cal­ly, retail trade, leisure and hos­pi­tal­i­ty, pro­fes­sion­al and busi­ness ser­vices, and edu­ca­tion­al and health services.

He reports that about 54 per­cent of the growth of invol­un­tary part-time employ­ment since 2007 comes from retail and leisure and hos­pi­tal­i­ty, while the remain­der of the growth most­ly stems from the oth­er two types of industries.

Invol­un­tary part-time work­ers are about equal­ly men and women, but work­ers in oth­er demo­graph­ic groups — black, His­pan­ic and prime-age work­ers, for exam­ple — more com­mon­ly suf­fer from not being able to find full-time jobs.

Notably, Gold­en found no evi­dence that the Afford­able Care Act’s employ­er man­date caused the rise in invol­un­tary part-time work.

Invol­un­tary part-time work­ers usu­al­ly work about half the hours of full-timers, get low­er rates of pay per hour and few­er, if any, ben­e­fits. Work­ers at fast-food chains and oth­er employ­ers that rely exten­sive­ly on part-timers also report that man­agers often reward or pun­ish work­ers by adjust­ing the num­ber of hours they are giv­en. Such irreg­u­lar sched­ul­ing of invol­un­tary part-time work can dis­rupt fam­i­ly life. On the oth­er hand, if work­ers have con­trol over their sched­ules, such vari­a­tion is one of the prin­ci­pal appeals of part-time work.

Gold­en reports that some exper­i­ments in pub­lic pol­i­cy sug­gest a way of reg­u­lat­ing part-time work to improve the prospects for part-time employ­ees. One approach used in many coun­tries and rec­om­mend­ed by the Inter­na­tion­al Labor Orga­ni­za­tion (ILO) is to require employ­ers to pro­vide part-timers the ben­e­fits of full-time work­ers, pro­rat­ed to the hours they work. The ILO rec­om­mends set­ting min­i­mum stan­dards for hours of work, as the Wash­ing­ton, D.C., city coun­cil did recent­ly for jan­i­tors in large com­mer­cial buildings.

Fol­low­ing the lead of leg­is­la­tion such as San Francisco’s ​“Pre­dictable Sched­ul­ing and Fair Treat­ment” ordi­nance, states and cities could enact rules giv­ing part-time work­ers a right of first refusal if addi­tion­al hours of work become avail­able. Gold­en also rec­om­mends adjust­ing unem­ploy­ment insur­ance to make sure that part-timers can benefit.

In the end, he argues, part-time work needs to make sense for work­ers at least as much as it does for employers.

“Although there has been a struc­tur­al shift toward invol­un­tary part-time labor, we can address it with spe­cif­ic pol­i­cy solu­tions that will help work­ers,” Gold­en says. ​“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.”