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Why would talented coders work for free? Information Systems Professor Tingting Nian, Lei Xu of the Toulouse School of Economics and Luís Cabral of the Stern School of Business at New York University teamed up to examine this very question by analyzing user activity on Stack Overflow, the largest online Q&A community for programmers. In 2019, Management Science published the results of their work in the study “What Makes Geeks Tick? A Study of Stack Overflow Careers.”  

Altruism may not be the only motivation behind open source software 

“Previous studies have only explored altruistic motivators,” Nian says, “or examined the gratification contributors received from improving the quality of open-source software projects, for example.” 

But what if previous studies had failed to measure a stronger, more practical motivational factor than altruism? What if users actively contributed answers to difficult coding questions simply to boost their reputation scores within the community as a means of helping them find a better job? 

“To the best of our knowledge, this is the first paper that empirically identifies and estimates the causal relation between changes in career status and voluntary contributions to online public goods as an indirect measure of career concerns,” the study explains. 

Their research examined the posting habits of users on Stack Overflow (SO) to determine motivational factors driving contributions. User reputations can grow by receiving positive votes for posting good answers to another user’s questions, but not for their edits to another user’s posts. In turn, users can use an affiliated service, Stack Overflow Careers, to link their Stack Overflow profile to their professional credentials, which potential employers can see.  

Stack Overflow users care about their reputation 

The study examined user editing and answering activities to look for clues about their motivations. As Nian explains, “If contributors were not concerned about their careers, then what we would expect to see is that the number of answers generated and the number of edits created would be moving in parallel over the time. Why? Because generating answers on the site increases their reputation scores while editing does not impact their reputation.” 

To get a better picture of how career concerns impacted Q&A and editing activities, the study looked at data of SO users who experienced a job change, analyzing the frequency and quality of activity in the three months before and after the career move.

The results showed that reputation-building activities increased significantly three months prior to a user’s job change but dropped off sharply three months later. There were a number of possible explanations for this. As Nian explains, “If the reduction in availability due to the job change was the primary reason for the drop in Q&A activity three months after landing the new job, then we should expect to see an equal impact on the user’s edit activity. But, again, that is not what we found.” 

Evidence of career-driven motivation 

According to their research, users who changed jobs reduced their Q&A contribution levels by 23% but those same users only reduced their reputation-neutral editing activities by 7.4%. “The dip in editing activity should be driven only by a lack of time availability,” she says. “But only one of those activities – answering questions – contributes to their reputation scores which can be leveraged to advance their careers. The difference between changes in these two contribution levels reveals how much of their activities were driven by employment concerns [16%], as opposed to any altruistic concerns.” 

The researchers were surprised by how much user’s Q&A activities ramped up before their job changes and how dramatically they declined afterward. The data revealed a clear link between planned career changes and an uptick in Q&A activity on Stack Overflow.  

Sites can benefit from building incentives for career-oriented users 

Nian thinks this research may offer insights to open-source software communities as they look for new ways to motivate user engagement. Nian says, “For example, GitHub and other sites could potentially implement reputation-based systems that reward contributors and increase their incentives to improve the quality and frequency of their activity.”   

So, is there any hope for quality code to be written by someone who is not being paid?  Nian thinks so. “I think that’s a good question, and it’s worth studying in further research,” she says. “The bottom line is that career advancement is a long-term factor that people are concerned about, and so they work to maintain reputation and demonstrate expertise within their community, and this helps users to write higher-quality code. 

Information Systems Professor Tingting Nian is a faculty member at the UCI Paul Merage School of Business. Her research studies of social media, online communities and economics of digital goods have won her numerous awards, including the 2014 INFORMS Conference on Information Systems and Technology Best Conference Paper Award, a WCAI Research Award from Wharton Customer Analytics Initiative, and several research grants including TFI Long-Term Research Grant and Hellman Fellowship. She received her PhD in Business Administration (specialized in Information Systems) from the Leonard N. Stern School of Business at NYU in 2015 and earned her Bachelor’s degree in Business Administration from Tsinghua University.