# Subtraction

> Improve something by removing parts before you think about adding new ones.

Chapter III, Problem solving · 3.18 · Origin: Leidy Klotz (2021) · Time: 15 to 30 min · Solo or group

**Use it when** the instinct is to add something and you suspect less would be better.

Interactive workspace: https://kogu.tools/tools/subtraction

## Abstract

Asked to improve something, most people add to it. In a series of experiments, Adams, Converse, Hales and Klotz found that people overlook changes that take something away, even when removing is the better fix, and that they miss them more often when they're busy.

This tool makes subtraction the first step. You list the parts of the thing you want to improve and ask what would happen without each one. Then you decide whether to keep it, shrink it or remove it, and only after that do you think about adding anything.

## Method

1. **Name the thing and the goal.** Say what you're improving and what better would mean, for example faster or cheaper.
2. **List every part.** Write down every step or feature involved, including the ones nobody ever questions.
3. **Imagine it gone.** For each part, ask whether anyone would notice if it disappeared, and what would break.
4. **Keep, shrink or remove.** Give a reason for each decision. If you can't say why a part exists, find out before you remove it.
5. **Look at what's left.** Read the leaner version as a whole and check that it still does the job.
6. **Then consider additions.** If something is still missing, add the smallest thing that fills the gap.

## When to use it

- A process has picked up extra approvals over the years and now crawls.
- A product or a slide deck feels crowded.
- Your calendar has no room left to think.

## Common pitfalls

- Removing something that was doing more work than it looked like. Ask why it exists first.
- Cutting only small, safe things and leaving the big ones alone.
- Turning it into a cost-cutting exercise. The point is a better result.
- Removing something without telling the people who relied on it.

## References

- Klotz, L. (2021). Subtract: The Untapped Science of Less. Flatiron Books.
- Adams, G. S., Converse, B. A., Hales, A. H., & Klotz, L. E. (2021). People systematically overlook subtractive changes. Nature, 592, 258-261.