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Episode 1022             Episode 1024
Episode 1023

Ninety-ninety rule
Thu, 2020-Feb-20 01:26 UTC
Length - 2:22

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Welcome to popular Wiki of the Day where we read the summary of a popular Wikipedia page every day.

With 920,879 views on Wednesday, 19 February 2020 our article of the day is Ninety-ninety rule.

In computer programming and software engineering, the ninety-ninety rule is a humorous aphorism that states:

The first 90 percent of the code accounts for the first 90 percent of the development time. The remaining 10 percent of the code accounts for the other 90 percent of the development time.

This adds up to 180%, making a wry allusion to the notoriety of software development projects significantly over-running their schedules (see software development effort estimation). The anecdote expresses both the rough allocation of time to easy and hard portions of a programming undertaking, and the cause of the lateness of many projects in their failure to anticipate their difficult, often unpredictable, complexities. In short, it often takes both more time and more coding than expected to complete a project.

The rule is attributed to Tom Cargill of Bell Labs, and was made popular by Jon Bentley's September 1985 "Programming Pearls" column in Communications of the ACM, in which it was titled the "Rule of Credibility". In some agile software projects, this rule also surfaces when a task is portrayed as "relatively done". This indicates a common scenario where planned work is completed but cannot be signed off, pending a single final activity which may not occur for a substantial amount of time.

This recording reflects the Wikipedia text as of 01:26 UTC on Thursday, 20 February 2020.

For the full current version of the article, see Ninety-ninety rule on Wikipedia.

This podcast is produced by Abulsme Productions based on Wikipedia content and is released under a Creative Commons Attribution-ShareAlike License.

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This has been Geraint. Thank you for listening to popular Wiki of the Day.


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