§ 99
Believability-Weighted Decisions
When a group counts every opinion the same, or defers to rank, the people who have actually done the thing before are outvoted by those who have not.
Keep in mind
Weigh views by track record, not by rank or headcount
What to do
Before a contested technical call, ask who has built or run this kind of thing before and whether it worked, and give their view more weight than headcount or title. Collect views in writing before the discussion so they stay independent, and look at both the plain tally and the weighted one; where they disagree, dig in rather than letting the weighted side win by default. Base believability on outcomes you can check, such as systems shipped and postmortems, and drop the weighting for questions nobody on the team has faced before.
Why it happens
In a design review everyone can form a view on every part, but only some of the room has built or run something like it. A show of hands gives the first-timer and the engineer who ran the last migration one vote each, and deferring to the most senior person only swaps one blind spot for another. Dalio's test is narrow and checkable: the most believable people have "repeatedly and successfully accomplished the thing in question" and can explain the cause and effect behind their view. Bridgewater shows the equal-weighted and the believability-weighted vote side by side: when they agree the matter is settled, and when they split, it tries again to resolve the disagreement and otherwise goes with the weighted vote. The split itself is where the information is.
When it stops applying
Wisdom of Crowds: when judgments are made independently, a plain equal-weight aggregate is hard to beat (the median guess of Galton's fairground crowd was within 1 percent of the ox's weight), and picking experts in advance bets on a track record that may not carry over to the new question.
Source
Ray Dalio, Principles: Life & Work (Simon & Schuster, 2017), work principle "Believability Weight Your Decision Making" (principles.com) — "the best decisions are made by an idea meritocracy with believability-weighted decision making", the most believable people being those who "have repeatedly and successfully accomplished the thing in question", and a tool that "displays both the equal-weighted average and the believability-weighted results". Netflix's culture memo (jobs.netflix.com, current version) makes the same point: "not all opinions are created equal". The counter-force is Francis Galton, Vox Populi (Nature, 1907).
Read the sourceCite this
Hammurabi, § 99, “Believability-Weighted Decisions.” https://kanywst.github.io/hammurabi/laws/believability-weighted-decisions/
BibTeX
@misc{hammurabi-believability-weighted-decisions,
title = {Believability-Weighted Decisions},
author = {{Hammurabi contributors}},
note = {Hammurabi, § 99},
url = {https://kanywst.github.io/hammurabi/laws/believability-weighted-decisions/}
}Related laws
- 76Disagree and CommitWaiting for everyone to agree is often slower than committing and correcting course if the call turns out wrong.
- 31Dunning-Kruger EffectPeople who are least skilled at something tend to overrate their ability the most.
- 05Law of TrivialityDiscussion goes to the parts everyone understands, not the parts that matter.