More People, Finished Later
About this app
The team as a living network of portraits: channels grow with n(n−1)/2 and new people tie up experienced colleagues as mentors. The app shows the U shape of the end date and the dip in output after a late addition (Brooks's law).
With explain mode: an AI tutor walks you through the app, points out what matters in the scene and answers your questions.
Brooks’s law and communication channels
In 1975 Fred Brooks wrote in "The Mythical Man-Month" that adding manpower to a late software project makes it later. He himself called the sentence an outrageous oversimplification. One reason lies in the communication paths: every pair in the team is a possible channel, so n people have n(n−1)/2. 6 people make 15 channels, 12 people make 66. Onboarding adds to this: experienced staff have to guide the newcomers and are missing from the actual work in the meantime.
What the app shows
The team of the case project Lumen (fictional) appears as a living network of portraits. A ring around each person shows how they use their time: productive work, coordination, mentoring or onboarding. Two curves show team output and the end date. Sliders set team size, number of new people, joining week and divisibility of the work. Small sub-teams with interfaces can be switched on. All model parameters are disclosed and explicitly assumptions. Only the channel formula is exact.
Things to try
Start with 6 people and four newcomers in week 20 and let the project run. Output first drops before it rises. Move the joining week earlier or later and watch the end date, which shows a U shape. Lower the divisibility of the work and see how little extra people then help. Switch on sub-teams and compare how the number of channels and the end date change.
Frequently asked questions
- What does Brooks’s law say?
- Brooks’s law states: adding manpower to a late software project makes it later. Extra staff cause onboarding effort and more coordination. In the time that remains, both can cost more output than the newcomers contribute.
- How many communication channels does a team have?
- With n people there are n(n−1)/2 possible pairs. A team of 6 has 15, a team of 12 has 66 and a team of 20 has 190 possible channels. The number grows quadratically with team size.
- Does more staff never help?
- It can, if the work divides well and someone joins early enough. Then the gain outweighs the onboarding cost. The app shows this through the divisibility slider and the joining week. Small sub-teams with clear interfaces also limit coordination effort.
- How reliable is the model in the app?
- The parameters for onboarding, mentor time and coordination loss are assumptions of a teaching model, neither measurements nor a forecast. Only the channel formula is fixed. The app is for understanding relationships, not for planning real projects.
Subject: Projektmanagement
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