meiersafe.com

Mike Meier · Lessons Learned and Murphy’s Corollary

“Anything that did not go wrong could not have gone wrong.”

Nobody believes in the literal truth of Murphy’s Law: “Anything that can go wrong will go wrong.” But if it were true, the corollary above would also be true. And we are surprisingly susceptible to that corollary: we take a positive outcome as evidence that a positive outcome was inevitable.

Start with the framework, a five-minute read, or run a briefing with the Briefing Kit.

Marshall Peak top landing, seen from the northwest: a 3D view of the real terrain from USGS elevation data, height exaggerated. The prevailing wind blows from the southwest, right to left, over the knob and curls down into a rotor on its lee side. The approach comes in from the right, fast and half crosswind, makes a diving turn across the front of the hill, and floats up the slope to touch down just below the top, through a layer of turbulence and wind gradient lying on the ground. Fast approach Diving turn, thenhalf crosswind up the slope Touchdown justbelow the top Rotor Turbulence andwind gradient Southwest wind 1,500 landings in 15 years
The top landing Mike made some 1,500 times over fifteen years, until the day it went wrong. Marshall Peak terrain from USGS elevation data, height exaggerated; the turbulence zone is illustrative.

What this site is

Meiersafe.com collects Mike Meier’s ideas on safety and risk. They draw on his 45 years of experience as a developmental, experimental and production test pilot in hang gliding. In 2015 he presented Lessons Learned and Murphy’s Corollary to the Society of Experimental Test Pilots: a paper about why a long record of success can hide real danger, and why the decision to go matters more than how well we fly.

Mike Meier on safety, in four minutes (2017).

The paper builds its argument one step at a time; this site follows the order of its abstract. Start with the “Would you play?” question below, then read:

The argument

  1. The framework: the whole argument, step by step
  2. Factor I · Deceptive mathematics
  3. Factor II · Murphy’s Corollary
  4. Factor III · The pressure to go
  5. The remedy · Analyze your successes

Applying it

  1. Case studies: the 1995 top landing, the 2015 certification launch, and four from aerospace
  2. Hard questions: is aviation inherently dangerous, is 100% safety possible, were we meant to fly?

Further thoughts

  1. Luck and uncertainty (2021)
  2. Three Random Thoughts On Safety: organizational safety culture, the 2D risk matrix and owning the risk (2025)

The source

  1. Lessons Learned and Murphy’s Corollary: the full paper, SETP, 2015

Every page in the reading order ends with a link to the next one, so you can read straight through.

How to use this site. Five minutes: the framework. An hour: the reading order above. Running a briefing or stand-down: the Briefing Kit and its one-page handout.

Also here: the Glossary, the Origins of the ideas, Speaking, About Mike and the License.

Would you play?

Imagine that you need a significant amount of money, with no obvious way to get it, and with serious consequences if you don’t. Someone offers you ten million dollars to play a single game of Russian roulette. One bullet, six chambers, one pull of the trigger. If the gun fires, you’re dead. If not, you get the ten million.

How many would take the offer? Mike’s guess, put to the symposium: not many. Yet a go decision that is 99 percent safe, made again and again, carries the same odds sooner than you’d think.

Try the numbers

A go decision that succeeds % of the time, made times, fails at least once 17% of the time: about one chance in 6.

The overall chance of success is the chance of each success raised to the power of the number of trials. At 99 percent, eighteen go decisions leave a one-in-six chance that at least one fails, the same odds as the revolver.

The framework

Two premises, three factors that work together against good decisions, and a remedy.

  1. Two premises. The primary determinant of safety is the quality of decision making. And when a negative outcome could be catastrophic, the go decision must be made only with a very high degree of confidence in a positive outcome.
  2. Factor I · Deceptive mathematics. High odds produce long strings of success, and each success seems to confirm the decision. But small risks, repeated, add up: 99 percent, eighteen times, is one chance in six of failure.
  3. Factor II · Murphy’s Corollary. If nothing did go wrong, we come to believe nothing could have gone wrong. A positive outcome is taken as proof that the decision was sound, and standards slowly slip.
  4. Factor III · The pressure to go. Deadlines, budgets, expectations and ego push us to go when we have doubts. A go decision relieves the pressure; a no-go only increases it the next time. In either case, reinforcement can operate in the wrong direction.
  5. The remedy · Analyze your successes. Stay aware of these tendencies, set a quantitative safety metric and a target beforehand, and measure every success against it, to find the ones that were really luck.

Further thoughts: Luck and uncertainty (Mike’s 2021 “Lucky or Good – Further Thoughts”) on skill, judgment and luck, and Three Random Thoughts On Safety (2025) on organizational safety culture, the 2D risk matrix and owning the risk.

Start reading: the framework Use it in a briefing