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 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: Only partial support for our hypotheses was observed. 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 not predict performance on the project. The use of hourly payments led to lower costs than fixed-price contracts, but not to improved processes or products. We plan to follow up these, to us unexpected, results with research on how to design more skill-predictive trialsourcing tasks, and when and why different project contexts give different contract consequences.

Teamwork is crucial in software development, particularly in agile development teams which are cross-functional and where team members work intensively together to develop a cohesive software solution. Effective teamwork is not easy; prior studies indicate challenges with communication, learning, prioritization, and leadership. Nevertheless, there is much advice available for teams, from agile methods, practitioner literature, and general studies on teamwork to a growing body of empirical studies on teamwork in the specific context of agile software development. This article presents the agile teamwork effectiveness model (ATEM) for colocated agile development teams. The model is based on evidence from focus groups, case studies, and multi-vocal literature and is a revision of a general team effectiveness model. Our model of agile teamwork effectiveness is composed of shared leadership, team orientation, redundancy, adaptability, and peer feedback. Coordinating mechanisms are needed to facilitate these components. The coordinating mechanisms are shared mental models, communication, and mutual trust. We critically examine the model and discuss extensions for very small, multi-team, distributed, and safety-critical development contexts. The model is intended for re- searchers, team members, coaches, and leaders in the agile community.

Empirical Standards are natural-language models of a scientific community's expectations for a specific kind of study (e.g. a questionnaire survey). The ACM SIGSOFT Paper and Peer Review Quality Initiative generated empirical standards for research methods commonly used in software engineering. These living documents, which should be continuously revised to reflect evolving consensus around research best practices, will improve research quality and make peer review more effective, reliable, transparent and fair.

Empirical Standards are brief public document that communicate expectations for a specific kind of study (e.g. a questionnaire survey). The ACM SIGSOFT Paper and Peer Review Quality Initiative generated empirical standards for common research methods in software engineering. These living documents, which should be continuously revised to reflect evolving consensus around research best practices, can be used to make peer review more transparent, structured, harmonious and fair.