Also known as:sufficient fact or data · FRE 702 basis · Rule 702 facts
Written by attorneys · grounded in primary & secondary sources — see below
A foundational requirement for the admissibility of expert testimony that the opinion rest on an adequate body of information drawn from the case or reliable sources to support the conclusions offered.
Sources & Authorities
How it applies
Common Examples
2
Expert Opinion Lacks Data Foundation
Spencer Silver sued Summit Bank after his investment account suffered unexpected losses. He offered an expert who concluded the bank had mismanaged the account based solely on the timing of a few withdrawals and a partial transaction summary. The expert had not reviewed the full account statements, trade confirmations, or internal bank communications. The court excluded the testimony because the expert lacked enough case-specific information to ground the opinion.
Thin Basis Undermines Causation Claim
Samantha Stone sued Stonehaven Properties after her crops failed, alleging contamination from a neighboring development. She offered an agronomist who attributed the losses to elevated nitrates based on a single visual inspection and one water sample taken months later. The expert had not conducted timely soil testing or reviewed development records from the relevant growing season. The court excluded the opinion because the limited information failed to support a reliable causal conclusion.
Put it into practice
Test Yourself
9
Practice Questions4
· 1 primary source
Select any source to read its text and confirm it supports the definition.
Federal Rules
Casebooks
Course Outlines
Study Supplements
Marsh v. Valyou977 So. 2d 543 (Fla. 2007)
Common questions
Frequently Asked
4
What happens when an expert's opinion rests on only timing of symptoms and a partial inspection summary?+
The court excludes the testimony. The opinion fails the requirement that expert testimony rest on sufficient facts or data because the expert lacked laboratory results, supply chain records, or reports from other affected individuals.
Supporting sources
Does an expert satisfy the sufficient facts or data requirement by relying on a computer simulation that uses assumed road conditions without inspecting the actual brakes?+
No. The court excludes the opinion because the simulation rests on assumptions rather than evidence-based inputs and the expert never examined the braking system at issue.
Supporting sources
When does a visual inspection and a single late water sample fail to provide sufficient facts or data for a causation opinion?+
The court sustains an objection to the testimony. The foundation is inadequate because the data are impressionistic and do not reliably reflect conditions during the relevant time period.
Supporting sources
May an expert base an opinion solely on a marketing brochure, a brief demonstration, and selected code snippets without reviewing full source code?+
No. The court excludes the testimony because the expert never examined the complete technical documentation or source code needed to compare the algorithms at issue.
Supporting sources
EvidenceRelevance and reasons for excluding relevant evidence · Opinions and expert testimonyNEXTGENFoundational