About a third of all employed workers in the UK have flexibility over their working hours, and about a fifth of people work from home on occasion. However, those with more freedom end up working more hours than those with more rigid schedules, finds a new study. Published in the journal European Sociological Review, scientists examined data that followed workers in Germany for several years to track how much overtime they did when they got more control over their working hours. They found the tendency for people to work more when given greater control held true even when controlling for things like level of authority and type of job. And this increase in working hours was greatest when workers had full autonomy over their working hours. It's thought people do this for a few reasons: one is the gift-exchange theory, or, that people work harder in exchange for the freedom given by their employers. It could also be because employers can give the freedom as part of a larger human resource package, which in many cases includes an income determined by performance outcomes. This allows employers to increase workloads without being confined to labor laws.