The Truck Factor (known by numerous other names including bus factor, lottery factor) is the minimum number of team members/people that must disappear from (or stop participating in) a project before it stalls out. It is essentially a way to define the number of people who are indispensable for a project.
Last year a group of Brazilian researchers proposed an algorithm to estimate the truck factor of software projects using data from version control systems and used the algorithm to compute the truck factor of 133 popular GitHub system. Recently, the group explored data from GitTrends to estimate the truck factor for some 17,000 GitHub projects. What they found will likely surprise and perhaps frighten some Web professionals as an estimated 2 percent of the projects monitored by GitTrends have a truck factor of 1.
The group noted that good software engineering practices certainly contribute to overcome truck factor episodes (documentation, tests, etc.; see again our previous paper). However, as an automatic tool, GitTrends does not consider these practices to estimate TFs.
In case the TF developers leave a project, this does not necessarily suggest the project will be discontinued, but that its maintenance and evolution will be in trouble. For example, bugs might take more time to get fixed and new features might take more time to be implemented.
This definitely shines the light on your side hustle. What's the truck factor of the projects you work on?