Feasibility studies — a market-sizing framework.

Last updated: April 2026

Quick answer

A defensible market-sizing study follows five steps: define the opportunity precisely, size top-down from published secondary data, size bottoms-up from addressable unit economics, triangulate the two ranges, and stress-test the assumptions against two or three scenarios. Skipping any one of these makes the final number look certain when it isn't. Show the math — especially the assumptions.

Market sizing is a method, not a number

A market-size figure quoted without the method behind it is a rumour. Decisions that ride on a rumour get unwound in the board meeting where someone asks "how did you get to that?" — so the method is the point, not the number.

This piece walks the five-step framework NUUN uses for feasibility studies. The same framework scales from a 4-week opportunity assessment to a 12-week cross-border expansion study.

Step 1 — Define the opportunity precisely

Write the opportunity as a sentence that names the buyer, the buying occasion, the geography, and the timeframe. "Canadian mid-market retailers buying a loyalty platform for annual contract value above $150k, within 24 months." If you can't write it in one sentence, you can't size it.

Step 2 — Size top-down

Start from the broadest published estimate of the category, then narrow through published filters: geography, company-size band, vertical, product fit. Keep a running table of the source, filter applied, and resulting number.

Expect three to five compounding filters. Each one is a multiplier between 0 and 1. The ceiling at the end of this step is your TAM proxy.

Step 3 — Size bottoms-up

Model unit economics from the buyer's side. Number of potential buyers × annual buying rate × average contract value × win probability against incumbents. Each coefficient is a judgment call — note them as explicit assumptions. Primary research (expert interviews, a short buyer survey) fills the gaps secondary data can't.

Step 4 — Triangulate

If top-down and bottoms-up land within ±25%, the range is defensible. If they diverge by more than 2×, one of the methods has an error — usually an under-narrowed filter on the top-down or a silently optimistic coefficient on the bottoms-up. Debug both.

Step 5 — Stress-test against scenarios

Build base, downside, and upside. Stress penetration rate, pricing, churn, competitive response. Report all three numbers — not a single point estimate with false precision. Decision-makers don't need certainty; they need the range and the sensitivities.

What the deliverable looks like

A NUUN feasibility-study deliverable carries: the opportunity statement, the secondary-data trace with every filter, the bottoms-up model as a spreadsheet (editable, not a screenshot), the primary-research appendix, the three scenarios, and a ranked list of entry risks. The point isn't the final number. It's the audit trail.

Sources & further reading

NUUN Research & Insights service pillar
NUUN Strategy & Growth service pillar
Statistics Canada — https://www.statcan.gc.ca/
US Census Bureau — https://www.census.gov/
Gartner — https://www.gartner.com/
IMF World Economic Outlook — https://www.imf.org/en/Publications/WEO

About the author

Feras Nasser

Principal, NUUN Digital

20+ years delivering quantitative feasibility studies and market-sizing work across NA and MENA; ESOMAR-trained, ISO 20252-aligned method governance.

Frequently asked.

What is TAM vs SAM vs SOM?

Total Addressable Market (TAM) is the revenue opportunity if every possible buyer bought. Serviceable Addressable Market (SAM) narrows to the segment your product can realistically serve. Serviceable Obtainable Market (SOM) is what you can plausibly capture in 3–5 years given competitors and channel reach.

How long does a feasibility study take?

Four to eight weeks depending on data availability. Weeks 1–2 scope and secondary data pull; weeks 3–5 primary research (expert interviews, buyer surveys); weeks 6–8 modeling, triangulation, and recommendation write-up.

What's the biggest mistake companies make in market sizing?

Picking a single method and calling it a number. Either all-tops-down (hand-wave from a Gartner chart) or all-bottoms-up (product of optimistic assumptions). The only defensible answer triangulates both and reports a range.

Do I need primary research for a feasibility study?

Usually yes. Secondary data gives you the shape; primary research (expert interviews, ICP surveys, pricing work) gives you the coefficients that matter. For B2B and niche markets it's almost always required because published data is thin.

How do I stress-test a market-size model?

Run three scenarios: base (central assumptions), downside (pessimistic on penetration and pricing), upside (optimistic on same). If the downside still clears your investment hurdle, you have a real opportunity. If only the upside clears, you have a hope, not a plan.

What sources count as credible for secondary data?

Government statistical agencies, central bank releases, industry trade bodies, reputable analyst firms (Gartner, Forrester, IDC, Mintel), and peer-reviewed academic research. Blog-based market-size numbers without a methodology page are not credible regardless of how often they're cited.

How do I size a market that doesn't exist yet?

Use analog markets, early-adopter cohort modeling, and stated-preference research. Define the switching trigger, size the population that hits the trigger annually, and discount aggressively — early markets rarely hit projected growth rates on schedule.