Imported from jpoutrin/product-on-steroids (pm-strategy/skills/market-segments/SKILL.md). Install upstream with npx skills add jpoutrin/product-on-steroids --skill market-segments. Copyright stays with the author.

Define & Prioritize Market Segments

Purpose

Break a market into 3–5 distinct, non-overlapping customer segments defined by the problem / job-to-be-done they share (not demographics alone), score each on size, attractiveness, and reachability, and recommend a single first/beachhead segment to focus on. Supports targeting, focus, and market-entry decisions by turning a broad "everyone" market into a ranked, defensible short-list.

When NOT to use: computing TAM/SAM/SOM dollar figures (use market-sizing — this skill scopes segments, it does not run the sizing math), building a single detailed buyer persona (this operates one level up, across segments), or competitive teardown (use competitor-analysis). This skill picks who first; it does not size the wallet or build the plan.

Inputs

• Required: the product/opportunity and its market boundaries — problem space, customer type (B2B/B2C), rough geography. If missing, ask for these three before segmenting; do not guess the scope.
• Optional: research/interview notes, customer or CRM data, existing personas (read and cite behavioral patterns and needs clusters), a preferred segmentation dimension, strategic constraints (channels you own, regions you can serve).

Output Contract

The deliverable is a segmentation & beachhead memo with these sections (see template.md):

1. Segmentation Basis — the market being split and the primary dimension(s) used (needs/JTBD-first, then behavioral/firmographic/demographic as modifiers); why these produce distinct, non-overlapping segments.
2. Segment Profiles — 3–5 segments, each with: a memorable name; the core job-to-be-done and desired outcome; the acute pain / trigger; who they are (behavioral + demo/firmo characteristics); and current alternatives/workarounds.
3. Prioritization Matrix — one table scoring every segment on Size, Attractiveness (pain intensity, willingness/ability to pay, growth, competitive whitespace), and Reachability (can you find and sell to them via a channel you have) on a stated scale, with a composite rank.
4. Beachhead Recommendation — the single first segment to win, why it beats the others (tie to matrix scores + fit + a foothold to expand from), and the top 1–2 assumptions to validate before committing.

Format: prose + one scoring table. Length: ~1–2 pages. Segments must be distinct and non-overlapping; every score carries a one-line justification, not a bare number.

GOOD (excerpt):

Segment B — "Solo bookkeepers at 1–5-person agencies." JTBD: close the month without chasing receipts by email. Trigger: quarterly VAT deadline. Alternative today: a shared spreadsheet + manual reminders.

Segment	Size	Attractiveness	Reachability	Composite
B	3 (med)	5 (acute pain, pays now)	5 (reachable via accounting-tool marketplaces)	13 — #1

Beachhead: Segment B — smaller than A but the pain is acute, they already pay for point tools, and the accounting-marketplace channel is one we own. Validate: that VAT-deadline urgency (not price) drives the switch.

BAD (excerpt):

"Our segments are 25–34-year-olds, 35–44-year-olds, and enterprises. All are big and attractive, so we'll target everyone." — fails: age buckets are demographics with no shared job, segments overlap and aren't distinct, scores are undifferentiated ("all big"), and there is no beachhead pick.

Process

1. Fix the scope — confirm problem space, customer type, and geography; restate the market being segmented.
2. Choose the basis — lead with needs/JTBD; layer behavioral/firmographic/demographic as modifiers. Confirm the dimensions yield distinct, non-overlapping cuts.
3. Define 3–5 segments — name each and write its core JTBD, desired outcome, acute pain/trigger, characteristics, and current alternatives.
4. Validate distinctness — check no two segments share the same job + buyer; merge or re-cut if they overlap.
5. Score — rate each segment on Size, Attractiveness, and Reachability on a stated scale, one-line justification per cell; compute a composite rank.
6. Pick the beachhead — recommend one first segment, justify vs. the runners-up, and name the foothold it opens for expansion.
7. Surface assumptions — list the 1–2 riskiest beliefs behind the pick and how to validate them.
8. Run the Quality Bar below; revise if any item fails; then return.

Quality Bar

Before returning, confirm:

• 3–5 segments, each defined by a job-to-be-done / problem — not demographics alone.
• Segments are distinct and non-overlapping (no two share the same job + buyer).
• Every segment has a named JTBD, an acute pain/trigger, and its current alternative.
• All segments are scored on Size, Attractiveness, and Reachability with a stated scale and a one-line justification per score — no bare numbers.
• A single beachhead is recommended and justified against the runners-up, tied to the matrix and to an expansion foothold.
• The 1–2 riskiest assumptions behind the pick are named with a validation step.
• Dollar sizing is deferred to market-sizing — this memo scopes, it does not size.
• If written to a file, it follows template.md — all 4 sections present, in order, headings matching (a skill-scoped hook re-checks this on write).

Validation & Eval

Scenario cards in evals/:

• market-segments-happy (happy path) — B2B tool with interview notes; full JTBD-based segmentation, scoring, and a defensible beachhead.
• market-segments-edge (edge) — sparse-data consumer market where segments must be inferred from behavior and distinctness is hard to hold.
• market-segments-adversarial (adversarial) — a demographics-only, "target everyone" ask the skill must re-cut into JTBD segments and force a single beachhead.

Pass bar: baseline overall ≥ 0.8; a change that drops overall > 0.05 fails.

References

Related Skills

• market-sizing — computes TAM/SAM/SOM dollar figures for the segments this skill defines; run it after picking the beachhead to size the wallet. This skill scopes, that one sizes.
• competitor-analysis — the "competitive whitespace" input to the Attractiveness score comes from a competitive read of each segment.

External Frameworks

• Clayton Christensen, Jobs to Be Done — segment by the job customers hire the product for, not by demographic attribute; the needs-first basis this skill leads with.
• Geoffrey Moore, Crossing the Chasm — the beachhead / bowling-pin logic of winning one focused segment first and expanding from that foothold.
• Bill Aulet, Disciplined Entrepreneurship, Steps 1 & 3 — market segmentation and selecting a single beachhead market as the discipline behind the prioritization here.