Compare and rank

Bump chart (rank changes)

Tracks changes in the rank of each item across ordered periods.

What it answers

How did the ranking change?

The question

How did our top five products move in the sales ranking this year?

Rank by quarter, 1 is highest. Atlas: #1, #1, #2, #3; Birch: #2, #3, #4, #5; Comet: #3, #2, #1, #1; Delta: #4, #5, #5, #4; Ember: #5, #4, #3, #2.

Illustrative data. It belongs to no company.

Tracking leaders across periods.

When actual magnitude differences matter more than rank.

Follow each item across rank positions; rank 1 is normally at the top.

Rank 1 is normally at the top.

Layout: Long table
Fields: Period: ordered date/number; Item: text; Value or Rank: number
One row is: One item in one period. What is the grain?
Rules: If deriving ranks, state ascending/descending order and tie rules. Explicitly distinguish rank from magnitude.
Optional: Optional precomputed Rank. Fill missing periods only under a stated rule.
Preparation: Compute ranks within each period using a declared ordering and tie rule; align item IDs across periods.
Units: Ordinal rank, normally 1=highest; not an interval or magnitude unit. State ties and eligible ranking population.

A long table: one row per observation, few columns. New data adds rows.

Data Jan: A30, B45; Feb: A50, B40. Derive descending ranks. A moves from rank 2 to rank 1.