AI tools can generate market size figures that are statistically plausible, confidently formatted, and completely fabricated. Large language models are trained on old reports and commentary. Asked for a TAM, they produce something that looks like research output — with no link to a verifiable primary source.
The number may be in the right ballpark. Or it may be off by a factor of three. Estimately.io exists as the alternative: analyst-verified data from a 70,000-report repository, human cross-checks, and a Sources sheet on every workbook.
How a hallucination reaches slide 4
A founder asks a general-purpose assistant for a sector TAM. It returns “$47 billion, 14% CAGR.” It looks credible. It is hard to verify. It goes into the deck as “industry research.” A sector-specialist investor recognizes it as implausible. The raise is wounded in the first ten minutes.
The problem compounds when AI figures are copied into blogs and secondary notes, then cited again. Provenance disappears. A fabricated number from two years ago can still be in a board pack today.
Investors who specialise in your sector often know the published size. If your number differs with no explanation, it reads as weak diligence — not as a unique insight.
What Estimately checks in 60 minutes
Numerical consistency: regions sum to global, CAGR matches the year path. Proportionality: country shares versus GDP, industrial output, consumption. Cross-reference: at least two independent primary sources; outliers investigated. Senior analyst review of the full Excel before sign-off.
The 60-minute window exists because that review cannot be rushed below a useful threshold. Instant AI is not a substitute for that step.
Questions AI cannot answer in diligence
Where does this figure come from? What is the base year? Does the definition match our market? Is it current? What is the methodology? Estimately’s Home sheet documents configuration and horizon; the Sources sheet names references; segmentation is analyst-reviewed against the stated market.
For pitch work, market entry, or fundraise sizing: from $20, free demo first, human-verified Excel after.