Technical question and answer (Q&A) websites provide a platform for developers to communicate with each other by asking and answering questions. Stack Overflow is the most prominent of such websites. With the rapidly increasing number of questions on Stack Overflow, it is becoming difficult to get an answer to all questions and as a result, millions of questions on Stack Overflow remain unsolved. In an attempt to improve the visibility of unsolved questions, Stack Overflow introduced a bounty system to motivate users to solve such questions. In this bounty system, users can offer reputation points in an effort to encourage users to answer their question. In this paper, we study 129,202 bounty questions that were proposed by 61,824 bounty backers. We observe that bounty questions have a higher solving-likelihood than non-bounty questions. This is particularly true for long-standing unsolved questions. For example, questions that were unsolved for 100 days for which a bounty is proposed are more likely to be solved (55%) than those without bounties (1.7%). In addition, we studied the factors that are important for the solving-likelihood and solving-time of a bounty question. We found that: (1) Questions are likely to attract more traffic after receiving a bounty than non-bounty questions. (2) Bounties work particularly well in very large communities with a relatively low question solving-likelihood. (3) High-valued bounties are associated with a higher solving-likelihood, but we did not observe a likelihood for expedited solutions. Our study shows that while bounties are not a silver bullet for getting a question solved, they are associated with a higher solving-likelihood of a question in most cases. As questions that are still unsolved after two days hardly receive any traffic, we recommend that Stack Overflow users propose a bounty as soon as possible after those two days for the bounty to have the highest impact.

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技术问答网站上的赏金：Stack Overflow 赏金的案例研究

技术问答（Q&A）网站为开发者提供了一个通过提问和回答相互交流的平台。Stack Overflow 是此类网站中最突出的。随着 Stack Overflow 上问题的数量迅速增加，所有问题的答案变得越来越困难，因此 Stack Overflow 上的数百万个问题仍未解决。为了提高未解决问题的可见度，Stack Overflow 引入了赏金系统来激励用户解决此类问题。在这个赏金系统中，用户可以提供声誉点来鼓励用户回答他们的问题。在本文中，我们研究了 61,824 名赏金支持者提出的 129,202 个赏金问题。我们观察到赏金问题比非赏金问题具有更高的解决可能性。对于长期未解决的问题尤其如此。例如，与没有悬赏的问题 (1.7%) 相比，悬赏 100 天未解决的问题更有可能得到解决 (55%)。此外，我们研究了对赏金问题的解决可能性和解决时间很重要的因素。我们发现： (1) 获得悬赏的问题比非悬赏的问题更有可能吸引更多的流量。(2) 赏金在解决问题的可能性相对较低的大型社区中特别有效。(3) 高价值赏金与更高的解决可能性有关，但我们没有观察到加速解决方案的可能性。我们的研究表明，虽然赏金不是解决问题的灵丹妙药，在大多数情况下，它们与更高的问题解决可能性有关。由于两天后仍未解决的问题几乎没有任何流量，我们建议 Stack Overflow 用户在两天后尽快提出赏金，以使赏金产生最大的影响。