Truck Number
The truck number (sometimes also the bus factor or lottery factor ) is a key figure for estimating project risks. The value describes the number of employees in a project who can be absent without endangering the project.
It is a term from risk management , a branch of project management . The key question for determining the key figure is:
"How many or few would have to be hit by a truck (or quit) before the project is incapacitated?"
"How many or few would have to be run over by a truck (or quit) before the project is crippled?"
The Truck Factor is a value proposed by Kent Beck that describes the probability of failure of a project if an employee fails and is a real number between 0 and 1. The worst value is 1 because it says that every team member is an indispensable specialist and thus the failure of (any) team member causes the project to fail. In order to avoid or reduce the risk, collective code ownership is used in extreme programming , in which every team member can change and thus take over any part of the source code.
In an alternative definition, the bus factor is the minimum number of unfavorably selected people who drop out until the project fails. The range of values here is a natural number greater than 0; here, too, the worst value is 1.
literature
- Michele Marchesi, Giancarlo Succi, Don Wells, James Donovan Wells, Laurie Williams: Extreme Programming Perspectives . Addison-Wesley, Boston et al. 2003, ISBN 0-201-77005-9 .
- Laurie Williams, Robert Kessler: Pair Programming Illuminated . Addison-Wesley, Boston et al. 2002, ISBN 0-201-74576-3 .
- Kent Beck : Extreme Programming. The manifest . Addison-Wesley, sl 2000, ISBN 3-8273-2139-5 .
Web links
Individual evidence
- ↑ Laurie Williams, Robert Kessler: Pair Programming Illuminated. P. 41