Managing assumptions during agile development

The assumptions that underlie software development often go unrecorded and form part of the implicit rationale on which design and implementation decisions are based. These assumptions can fail at any time, with serious consequences. This paper presents a lightweight approach to assumption management (AM) designed to suit agile development. Assumptions were monitored for three months within a small agile team. Two key indicators were proposed for measuring AM success but only one was detected in the research results. A number of strong correlations were found between properties of assumptions. Data collection largely depended on the subjective judgements of the first author, but they were validated with some success by his colleagues. In some ways, assumption management was found to complement agile development. However, AM was not fully integrated into the team's development process, due to difficulty in adopting an 'assumption-aware ' way of thinking. Suggestions are offered on how this transition may be eased, and on how others might wish to build on this research.