Today’s gig economy means more people are working as independent contractors, taking on a variety of short-term paid projects to make ends meet. Why is this approach more appealing than a full-time position, and what motivates gig economy workers to take on a job? Several recent studies of ride-share drivers and other contract employees offer some insight into why they take jobs—and the results might surprise you.

1. Consistency

While you might think gig economy workers take on a collection of side jobs out of an entrepreneurial drive, most are motivated by a desire for consistency. A study from Wharton and New York University found that the longer contract employees worked with one company, the more likely they were to continue working for them. That is, rather than hopping around looking for the next best job, contract workers were generally happy to stick with one business in hopes of “more consistent revenue streams.”

2. High Pay

Money is always a given motivation for any kind of work, but the same Wharton study noted that the more money gig workers were offered for performing a job, the more likely they were to work hard: the more people are paid, the harder and longer they are willing to work. Assign them a shift with a guaranteed wage, however, and they will be less motivated to get work done. But once there is a big monetary reward connected directly to their effort, they’ll be highly motivated to work hard.

3. Savings Goals and Flexibility

Wharton researchers also discovered that many gig workers took on an extra side job not just to make ends meet, but to supplement their income to reach a specific savings goal, such as a big vacation. So extra gig economy jobs aren’t always a function of necessity but of a desire to earn more and buy more. Over time, gig workers found they enjoyed the flexibility that comes with their side jobs, the researchers said, and predict we may see more even more people moving into the gig economy in the future.

4. Social Opportunity

A Harvard Business Review article suggests that for part-time contract workers, taking on an extra job has a social reward. Many of these workers take on the work as a luxury, earning extra income while filling in extra time between other more demanding employment, retirement, and family time. These workers are hobbyist employees who do the work simply because they like it.

While some people take on extra jobs in the gig economy to support their family with a consistent income, many are motivated by other reasons, namely the chance for personal fulfillment while earning an extra income. While these hobbyist workers many not stick around in their jobs long-term, the research is clear: the gig economy is here to stay.