always-compare

Skill: Always Compare

Purpose

A number alone is not an insight. "Conversion rate is 3.2%" tells the reader nothing actionable — they cannot tell if that is a crisis or a record high. This skill enforces one rule: every metric ships with a comparison.

When to Use

Before presenting ANY number to the user — in chat, in a report, in a chart caption, in a Slack message, or on a slide. This runs on every analysis output, alongside question-framing (which runs at the start; this one runs at the end).

The Rule

Never show a number alone. Anchor it to at least one comparison.

Pick the comparison that best serves the decision. In priority order:

#	Comparison Type	Use When	Example
1	vs. prior period	The question is "is this changing?"	"down from 4.1% last month"
2	vs. benchmark / average	The question is "is this normal?"	"below the 3.8% site-wide average"
3	vs. another segment	The question is "who is affected?"	"vs. 5.4% on desktop"

Two comparisons beat one. A prior-period delta plus a benchmark tells the reader both the direction and the altitude. Use both when you have both.

Instructions

Step 1: Find every number in your draft output

Scan the response you are about to send. Every figure — headline stats, table cells, chart annotations, sentences in the narrative — is in scope.

Step 2: Attach a comparison to each one

For each metric, ask: compared to what? Then pull the comparison from the data:

• Prior period: same metric, previous week / month / quarter (match the grain of the metric)
• Benchmark: site-wide average, cohort average, target, or historical baseline
• Segment: the same metric for a contrasting slice (mobile vs. desktop, new vs. returning, channel A vs. B)

Compute the comparison in the same query where practical — it is cheaper and less error-prone than a second round trip, and it guarantees the filters match.

Step 3: State the delta, not just both numbers

Do the subtraction for the reader. "3.2%, down from 4.1%" is better than "3.2% (last month: 4.1%)". Give direction (up/down) and magnitude (absolute points or relative %) — and be explicit about which you are using: "down 0.9pp (a 22% relative decline)".