What the number actually is

• What a Sales Rank Actually Measures

  Not units sold, not revenue, not popularity. A position in an ordered list, recalculated constantly, behaving in ways that surprise people.

  Explainer

• Rank Is Relative, and What That Breaks

  Your position changes when other people's sales change. Every conclusion drawn from a rank movement has to survive that fact first.

  Explainer

• Rank Is Not Sales, and the Conversion Problem

  Every rank-to-sales table is reverse-engineered from small self-reported samples. What they are worth and how to use one honestly.

  Analysis

• Category Ranks Versus the Overall Rank

  A product carries several ranks at once and they behave differently. Which one to track depends on the question, and mixing them is a common source of nonsense.

  Reference

• How Often Rank Updates, and What That Hides

  The refresh cadence is unpublished and varies by catalogue depth. It determines the shortest event your data can possibly detect.

  Explainer

• Rank Decay and the Half-Life of a Sale

  A sale improves rank immediately and the effect fades. The fade rate is the most useful undocumented property of the system.

  Explainer

• What Rank Data Cannot Tell You

  A list of questions people routinely ask of this data that it cannot answer, and what to use instead for each.

  Reference

7 notes