Defining Sustainability through Developers' Eyes: Recommendations from an Interview Study

Defining 'software sustainability' in the context of research, and determining how best to support it, remains a considerable challenge. The research reported here approaches the question from a new direction by asking research software developers to provide their own experience of and opinions about sustainability.
Two main themes emerged from the study: intrinsic sustainability - concerned with aspects of the software itself - and extrinsic sustainability - concerned with the environment in which it is developed. A key finding is that developers consider sustainability is less at the level of the research project that funds it, and more at the level of the software artefact itself, and ensuring that the functionality it represents can be re-used in some capacity in the future. We propose recommendations to improve sustainability, focusing in particular on community building, improving software quality and increasing motivation.