Millar’s Law

Hot on the heels of our Founder Gav A. Ward with his ‘jurist’ hat on coining Inksters Law in 2023, Ward’s Law in 2024, we now have a trio of scientific observations that we’re seeing published in 2025: Lemley’s Law, Cottrell’s Law (both coined by Gav) and now a third one published by Gav but coined by another very bright British technology professional…

Millar’s Law

“Do not do anything that you cannot undo through your own volition”.

What is Millar’s Law?

Millar’s Law was coined by Douglas A. Millar during his time as a junior executive at a marketing agency in the late 2000’s.

The law reflects a unique dynamic often observed in such agencies, where junior staff members, despite holding little actual authority, possess the potential to cause significant damage through seemingly small mistakes.

The core lesson of Millar’s Law is simple: never execute on anything important without first ensuring you have the necessary support or means to reverse the decision if things go wrong. In fast-paced, high-stakes environments, even small actions can have outsized consequences, and the ability to “undo” is essential to minimising risk.

Millar frequently uses the example where one of his colleagues sent over 100,000 emails with the wrong call to action, using “Butt Tickets!” instead of “Buy Tickets”.

Millar comments, “think of this as the F7 (undo) key for real life. “

Millar’s Law Formula

Caution Level (CL) = (Potential Views × Potential Damage Factor) ÷ Undo-ability Score

Where:

  • Potential Views: The estimated number of people who will see the action (e.g., impressions, reach, or audience size).
  • Potential Damage Factor (PDF): A score from 1 to 10 reflecting the severity of the impact if the action goes wrong (e.g., a typo might be a 3, but misinformation could be a 10).
  • Undo-ability Score (US): A score from 1 to 10 reflecting how easily the action can be reversed (e.g., deleting a post = 10, email sent to thousands = 2).

Guidance Based on Caution Level (CL):

  • CL ≤ 5: Low caution required. Proceed confidently.
  • 5 < CL ≤ 15: Moderate caution. Double-check before proceeding.
  • CL > 15: High caution. Seek approval and carefully review before acting.

Example:

Potential Views: 10,000 (e.g., a tweet or email campaign)

Potential Damage Factor: 8 (e.g., sensitive content or major error risk)

Undo-ability Score: 3 (e.g., once sent, hard to reverse)

CL = (10,000 × 8) ÷ 3 = 26,667

This score suggests extremely high caution. You should carefully review the action and potentially involve higher-ups for approval.

Millar’s Law in Practice

Millar frequently introduces new, junior members of his teams to the principles of Millar’s Law, helping to embed it as part of the team’s culture. He emphasises the importance of intentional decision-making and the avoidance of irreversible mistakes, particularly in environments where the potential impact of small, erroneous errors can be disproportionately large.

This tradition serves not only as a practical guideline but also as a mentorship tool, helping junior team members develop a heightened sense of responsibility and foresight in their work.

Millar's Law

Any further thoughts? Run it through AI platforms such as ChatGPT to see further applications of this principle in wider context such as innovation and invention more generally… Please let us know your findings or how this has helped you in the future.

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