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Plate PRIN·002 · PrincipleGrid B2 · Rev. 2026-08-14

Pareto Principle

A small share of features carries most of the use, which is a prompt to go and measure rather than an excuse to cut.

PrincipleCraft conventionFoundational

Definition

The observation, named after Vilfredo Pareto, that outcomes are often unevenly distributed, with roughly eighty percent of effects coming from twenty percent of causes. In product work it is used to focus effort on the small set of features that carries most usage.

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

On this plate
  1. 1Definition
  2. 2The dangerous version
  3. 3Better uses of the principle
  4. 4Using the ratio responsibly
  5. 5In practice
  6. 6Local chart
  7. 7Sources
  8. 8Continue from here

Reach for this when

  • Prioritising a roadmap or a redesign.
  • Deciding what belongs in the primary interface surface.
  • Reviewing candidates for deprecation.

Common mistakes

  • Treating the ratio as fixed.
  • Deleting the long tail without segmenting usage.
  • Optimising the top twenty percent while the remaining paths rot.
  • Treating an observed ratio as a law, then explaining away the cases where the numbers do not fit.

The dangerous version

Used carelessly, this principle justifies removing the long tail. That is usually wrong. Low-usage features are frequently the ones a small, high-value segment depends on absolutely, and a feature used by two percent of users may be used by eighty percent of your enterprise revenue.

The correct move is usually not removal but demotion: keep the capability, move it out of the primary path, and stop paying design attention proportional to its footprint rather than its value.

Better uses of the principle

  • Give the top tasks the shortest paths and the most design attention.
  • Demote rarely used features to a secondary surface rather than deleting them.
  • Prioritise performance work on the highest-traffic routes.
  • Segment usage before concluding a feature is unused. Aggregate percentages hide dependent minorities.

Using the ratio responsibly

Do

  • Measure your own distribution before assuming it is eighty and twenty.
  • Design the common path to be fast and the rare path to be possible.
  • Check who the tail is before removing it. Rare overall can mean essential for one segment.

Do not

  • Quote the ratio as though it were measured for your product.
  • Delete the twenty percent of features that twenty percent of revenue depends on.
  • Optimise the top of a distribution that has two peaks.

In practice

  1. i.

    Toolbar versus overflow menu

    Editors

    Promoting the four most-used tools to the toolbar and moving the rest to an overflow menu preserves capability while shortening the common path.

  2. ii.

    Segmenting before deprecating

    Enterprise software

    A feature at three percent overall usage turned out to be used by every customer above a certain contract size. Aggregate numbers would have recommended deleting it.

  3. iii.

    The rarely used feature that kept the contract

    Reading the tail

    Bulk export was used by four percent of accounts, and those accounts were the largest ones. Usage frequency and commercial weight are different distributions, and only one of them was on the dashboard.

Local chart

PRIN·002 · Region I · Grid B2

This entry and the entries it is stated to connect with. Each line is labelled with what the connection means.

Availability HeuristicBIAS·011 · WHY THIS WORKSSunk Cost FallacyBIAS·014 · WHY THIS WORKSBulk ActionsPAT·017 · APPLIED THROUGHInformation ArchitectureRES·015 · APPLIED THROUGHProduct AnalyticsRES·010 · APPLIED THROUGHPrioritising Design WorkFLOW·006 · APPLIED THROUGHStory MapTPL·006 · OFTEN USED WITHFlexibility and Efficiency of UseHEUR·007 · RELATED CONCEPTOccam's RazorPRIN·001 · RELATED CONCEPTProgressive DisclosurePRIN·003 · RELATED CONCEPT

Sources

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

  1. [1]

    Cours d'économie politique

    V. Pareto, 1896

    The original observation concerned income distribution, not software features.

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

A DashboardA Data TableAn Enterprise Workflow

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.

Related concept

Connected closely enough to change how you apply this.