Also known as: reasonable degree of scientific certainty · reasonable certainty
Written by attorneys · grounded in primary & secondary sources — see below
A standard of proof that requires an expert witness to express an opinion as more likely than not true on the basis of accepted scientific methodology rather than speculation or mere possibility. The phrasing prevents the trier of fact from receiving conclusions that rest on unquantified degrees of likelihood.
Rhea Reynolds, an insurance executive, received a signed coverage placement request from Riverfront Developments that listed only total premium and aggregate limit. At trial an expert actuary testified that the essential reinsurance terms could be identified with reasonable scientific certainty from industry practice and the parties' prior meetings. The court held the writing satisfied the statute of frauds.
Rebecca Ross executed a will that referred to an existing schedule of personal property. An expert in estate administration testified that the schedule could be identified with reasonable scientific certainty from the will's language and the testator's contemporaneous files. The court allowed incorporation by reference.
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Police obtained a warrant for an unidentified suspect in a robbery. A forensic facial-recognition expert testified that the description matched the defendant with reasonable scientific certainty based on surveillance footage and database algorithms. The magistrate issued the warrant.
Rina Rahman bought a defective machine from Redline Automotive after a misrepresentation about its capacity. An accounting expert testified that her lost profits could be calculated with reasonable scientific certainty from production records and market data. The court awarded the additional contract damages.
Roland Rhodes spent substantial sums preparing to perform a supply contract that Reliance Insurance later repudiated. A damages expert testified that the net reliance loss, after subtracting any loss the breaching party could prove with reasonable scientific certainty, equaled a specific dollar amount. The court awarded reliance damages.
Rachel Ramirez claimed lost profits after a supplier's breach. A forensic economist testified that the amount of loss could be established with reasonable scientific certainty from historical sales data and industry benchmarks. The court permitted recovery of the proven amount.
An expert must use the phrase when the opinion rests on application of accepted methodology to case-specific facts and the expert can state the conclusion is more likely than not true. The requirement prevents testimony that rests only on possibility or speculation.
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No. The standard requires only that the expert's conclusion be more probable than not on the basis of reliable methods. Courts accept reasonable estimates when absolute precision is impossible.
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The opinion is inadmissible because it fails to meet the requirement that factual inferences be stated with sufficient certainty. The trier of fact may not rely on conclusions that remain speculative.
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A plaintiff must prove the existence and amount of pecuniary loss with reasonable certainty. Expert testimony phrased to that standard supplies the required evidentiary foundation for damages such as lost profits or repair costs.
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…mitigates the degree of criminality or punishment, we think the State may assure itself that the fact has been established with reasonable certainty. To recognize at all a mitigating circumstance does not require the State to prove its nonexistence in each case in which the fact is put in issue, if in its judgment this would be too…