  This technical report records and discusses the Second Workshop on
Sustainable Software for Science: Practice and Experiences (WSSSPE2). The
report includes a description of the alternative, experimental submission and
review process, two workshop keynote presentations, a series of lightning
talks, a discussion on sustainability, and five discussions from the topic
areas of exploring sustainability; software development experiences; credit &
incentives; reproducibility & reuse & sharing; and code testing & code review.
For each topic, the report includes a list of tangible actions that were
proposed and that would lead to potential change. The workshop recognized that
reliance on scientific software is pervasive in all areas of world-leading
research today. The workshop participants then proceeded to explore different
perspectives on the concept of sustainability. Key enablers and barriers of
sustainable scientific software were identified from their experiences. In
addition, recommendations with new requirements such as software credit files
and software prize frameworks were outlined for improving practices in
sustainable software engineering. There was also broad consensus that formal
training in software development or engineering was rare among the
practitioners. Significant strides need to be made in building a sense of
community via training in software and technical practices, on increasing their
size and scope, and on better integrating them directly into graduate education
programs. Finally, journals can define and publish policies to improve
reproducibility, whereas reviewers can insist that authors provide sufficient
information and access to data and software to allow them reproduce the results
in the paper. Hence a list of criteria is compiled for journals to provide to
reviewers so as to make it easier to review software submitted for publication
as a "Software Paper."
