How many software developers would have to leave a project to make development come to a halt? That number is the bus factor. The macabre meaning behind the bus factor is the number of developers that would need to get hit by a bus to halt development (but it's often lighter to think about members winning the lottery, not that anyone who knows about statistics would actually play the lottery).

The "bus factor" is the minimum number of team members that have to suddenly disappear from a project before the project stalls due to lack of knowledgeable or competent personnel.

How do you increase the bus factor of your projects?

It's important to note that many employees are solving to reduce bus factor (rightly or wrongly). Here's some biases to correct for: