Why We Estimate Badly, and Why That Is Fine

A note on planning fallacy, buffers, and the social function of a deadline

This is a placeholder essay body for Why We Estimate Badly, and Why That Is Fine. Replace it with your own writing. The structure below mirrors the shape of a long-form piece: an opening, a few sections with headings, a pull-quote, and a closing.

The problem

Most tools are designed for a single person sitting alone at a desk. But most meaningful work happens between people. The interface rarely acknowledges that anyone else exists. Presence indicators are the usual exception, and they are often the first feature to be switched off.

When we design as if the user is alone, we optimise for throughput and ignore the slower, messier coordination work that actually determines whether a project succeeds. The research on computer-supported cooperative work has said this for decades.

A small example

Consider a shared document. The cursor of a collaborator is a tiny signal, but it changes how you write. You slow down near them. You leave a comment instead of overwriting. The interface made someone else visible, and your behaviour changed.

A placeholder diagram of two cursors in one document
Two cursors in one document. A placeholder figure.

Design is not just how it looks and feels. Design is how it works for the people around you.

What we could do instead

Three ideas keep resurfacing in my notes:

  • Make other people ambiently visible, without demanding attention.
  • Prefer reversible actions, so coordination mistakes are cheap.
  • Give groups a shared history they can point at.

Where this breaks down

None of these are free. Every signal you add is a small tax on attention, and the budget is finite. A useful test: remove the signal for a week and see whether anyone asks for it back. I wrote about that budget in Quiet Interfaces.

Closing thoughts

I don't think this is solved. I think it is under-explored, which is a much more interesting state for a problem to be in.

Mentions around the web

A careful piece on shared context. The section on reversible actions is the part I keep sending to people on my team.
Really enjoyed this one. The framing of interfaces as social spaces is going straight into my notes.
The layout of this site is a pleasure to read on a phone. Also, strong agree on the argument.
Adding this to the list of pieces that convinced me to stop posting to timelines first.