Determinants of quality, latency, and amount of Stack Overflow answers about recent Android APIs.

Stack Overflow is a popular crowdsourced question and answer website for programming-related issues. It is an invaluable resource for software developers; on average, questions posted there get answered in minutes to an hour. Questions about well established topics, e.g., the coercion operator in C++, or the difference between canonical and class names in Java, get asked often in one form or another, and answered very quickly. On the other hand, questions on previously unseen or niche topics take a while to get a good answer. This is particularly the case with questions about current updates to or the introduction of new application programming interfaces (APIs). In a hyper-competitive online market, getting good answers to current programming questions sooner could increase the chances of an app getting released and used. So, can developers anyhow, e.g., hasten the speed to good answers to questions about new APIs? Here, we empirically study Stack Overflow questions pertaining to new Android APIs and their associated answers. We contrast the interest in these questions, their answer quality, and timeliness of their answers to questions about old APIs. We find that Stack Overflow answerers in general prioritize with respect to currentness: questions about new APIs do get more answers, but good quality answers take longer. We also find that incentives in terms of question bounties, if used appropriately, can significantly shorten the time and increase answer quality. Interestingly, no operationalization of bounty amount shows significance in our models. In practice, our findings confirm the value of bounties in enhancing expert participation. In addition, they show that the Stack Overflow style of crowdsourcing, for all its glory in providing answers about established programming knowledge, is less effective with new API questions

Model variable descriptions.

<p>Model variable descriptions.</p

Number of answers per question, Poisson GLM.

<p>Number of answers per question, Poisson GLM.</p

Time to first good answer models, log minutes, before 2 days.

<p>Time to first good answer models, log minutes, before 2 days.</p

Qualitative coding guide for questions about Android APIs.

<p>Qualitative coding guide for questions about Android APIs.</p

Time since API addition for 50 question case study, per manual classification group (2-sided t-test p < 0.05; 2-sided Wilcoxon rank-sum test p < 0.05).

<p>Time since API addition for 50 question case study, per manual classification group (2-sided t-test p < 0.05; 2-sided Wilcoxon rank-sum test p < 0.05).</p

Residual vs. fitted value plots for combined and split time to answer models (lowess smoothed).

<p>Residual vs. fitted value plots for combined and split time to answer models (lowess smoothed).</p

Answer quality models (bad, good), logistic regression.

<p>Answer quality models (bad, good), logistic regression.</p