Context

To ensure the success of software projects, it is essential to select skilled developers and to use suitable work contracts.

Objective

This study tests two hypotheses: (i) the use of work-sample testing (trialsourcing) improves the selection of skilled software developers; and (ii) the use of contracts based on hourly payment leads to better software project outcomes than fixed-price contracts.

Method

Fifty-seven software freelancers with relevant experience and good evaluation scores from previous clients were invited to complete a two-hour long trialsourcing task to qualify for a software development project. Thirty-six developers completed the trialsourcing task with acceptable performance, and, based on a stratified random allocation process, were asked to give a proposal based on an hourly payment or a fixed-price contract. Eight hourly payment-based and eight fixed-priced proposals were accepted. The process and product characteristics of the completion of these 16 projects were collected and analysed.

Results and Conclusion

While the use of trialsourcing may have prevented the selection of developers with insufficient skills, the performance on the trialsourcing task of the selected developers did, to a large extent, not predict their performance on the projects. The use of hourly payments seems to have led to lower costs than fixed-price contracts, but not to improved processes or products. We plan to follow up these results with research on how to design more skill-predictive trialsourcing tasks, and when and why different project contexts give different contract consequences.

中文翻译：

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试采购的现场实验以及合同类型对外包软件开发的影响

语境

为了确保软件项目的成功，必须选择熟练的开发人员并使用合适的工作合同。

客观的

这项研究检验了两个假设：（i）使用工作样本测试（Trialsourcing）提高了熟练软件开发人员的选择；（ii）使用按小时付款的合同比固定价格合同可带来更好的软件项目成果。

方法

邀请了57位具有相关经验并在以前的客户中获得良好评估分数的软件自由职业者，以完成为期两个小时的试用采购任务，以符合软件开发项目的条件。三十六名开发人员以可接受的性能完成了试验采购任务，并根据分层随机分配过程，被要求根据小时付款或固定价格合同提出建议。接受了八个基于小时的付费方案和八个固定价格的方案。收集并分析了这16个项目的完成过程和产品特性。

结果与结论

虽然使用试用资源可能会阻止选择技能不足的开发人员，但是所选开发人员在试用资源上的表现在很大程度上不能预测他们在项目上的表现。按小时付款似乎比固定价格合同降低了成本，但没有改善流程或产品。我们计划在研究如何设计更具技能预测性的试验采购任务以及何时以及为什么不同的项目环境产生不同的合同后果时进行研究，以跟踪这些结果。