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PrincipleCraft conventionFoundational

Occam's Razor

Among competing solutions that meet the requirement, prefer the one with fewest assumptions and moving parts.

Definition

A principle of parsimony attributed to the fourteenth-century logician William of Ockham. Applied to design, it argues for the solution that satisfies the requirement with the least additional machinery, not the solution that is smallest.

Craft convention. True because the industry converged on it. Breaking it costs familiarity, not correctness.

On this page
  1. Definition
  2. Questions the razor asks
  3. Applied to interfaces
  4. In practice
  5. Sources
  6. Continue from here

Questions the razor asks

  1. 1.What is the actual requirement, stated without reference to a solution?
  2. 2.What is the smallest thing that meets it completely?
  3. 3.What does each additional element buy, and for whom?
  4. 4.What breaks if it is removed? If nothing, remove it.
  5. 5.Is the complexity load-bearing, or is it habit?

Applied to interfaces

The most common wins are removal of things that were never needed: a field nothing consumes, a confirmation for a reversible action, a setting with one sensible value, an animation that delays without informing.

The most common failures are removals that push complexity onto the user rather than out of the system. That is Tesler's Law, and the two principles have to be read together.

In practice

Removing the confirm password field

Signup

A show-password toggle plus a clear error on failed login achieves the same protection against typos with one field instead of two, and it works better for password managers.

One setting instead of three

Application preferences

Three related toggles that are never set independently are one setting with a good default. Check the analytics before assuming users want the granularity.

Sources

Where a source establishes something narrower than the popular reading of it, the note says so.

  • Attributed to William of Ockham

    Scholastic philosophy, fourteenth century

    A principle of logic and explanation, later adopted into design practice. It has no experimental basis and is not a UX finding.

Continue from here

Each link says what the connection is, so you can tell a principle from an alternative from a thing people mix this up with.

Applies when you are designing

Settings

Why this works

The reasoning this entry rests on.

Applied through

Where this shows up as a concrete interface decision.

Often used with

These usually appear in the same screen or the same decision.

Short definition

The one-paragraph version, for when that is all you need.

Related concept

Connected closely enough to change how you apply this.