  The global value of open source software is estimated to be in the billions
or trillions worldwide1, but despite this, it is often under-resourced and
subject to high-impact security vulnerabilities and stability failures2,3. In
order to investigate factors contributing to open source community longevity,
we monitored thirty-eight open source projects over the period of a year,
focusing primarily, but not exclusively, on open science-related online
code-oriented communities. We measured performance indicators, using both
subjective and qualitative measures (participant surveys), as well as using
computational scripts to retrieve and analyse indicators associated with these
projects' online source control codebases. None of the projects were abandoned
during this period, and only one project entered a planned shutdown.
  Project ages spanned from under one year to over forty years old at the start
of the study, and results were highly heterogeneous, showing little commonality
across documentation, mean response times for issues and code contributions,
and available funding/staffing resources. Whilst source code-based indicators
were able to offer some insights into project activity, we observed that
similar indicators across different projects often had very different meanings
when context was taken into account.
  We conclude that the individual context-free metrics we studied were not
sufficient or essential for project longevity and sustainability, and might
even become detrimental if used to support high-stakes decision making. When
attempting to understand an online open community's longer-term sustainability,
we recommend that researchers avoid cross-project quantitative comparisons, and
advise instead that they use single-project-level assessments which combine
quantitative measures with contextualising qualitative data.
