MENTAL MODEL · M0222

Bus Factor

BusinessHigh supportManagement

Included

Version 1.0.0 · Updated 2026-07-28

CORE DEFINITION

The bus factor (aka lottery factor, truck factor, or circus factor) is a measurement of the risk resulting from information and capabilities not being shared among team members, derived from the phrase "in case they get hit by a bus".

SCAFFOLDING EFFECT

psychology

Reduce cognitive load

anchor

Anchor fast decisions

The bus factor refers to "how many people in the project would need to be hit by a bus for the project to be paralyzed" — that is, the degree to which critical knowledge/permissions are concentrated in a few people. The lower the factor, the higher the risk of single point of failure; it measures the team's robustness (bus factor = 1 is most dangerous).

MINIMUM ACTION

In progress 0/4

Practice this model in one real situation:

Inventory critical tasks and the sole individuals who hold the knowledge
calculate the number of people whose absence would halt each task
for low-factor items, implement documentation, cross-training, and permission sharing
set a target bus factor of at least 2 or higher.

Check to track your progress (stored locally)

Learning progress0%

account_treeGenealogyexpand_more

menu_bookReferencesexpand_more

Source support: Explicit

link
en.wikipedia.orghttps://en.wikipedia.org/wiki/Bus_factorZH · Explicit
verified

RELATED MODELS