Expertpays Rules: Dial 703705 for Optimal

Boy I would love my expert to talk about something, but that something is inadmissible. Darn! A refrain as old as counselor time. Luckily, the rules of evidence are a stress-relieving salve for the weary. Expert witnesses, as we know, can testify to facts without having direct knowledge of those facts. And from this crucial inch given, a mile of discretion has appeared within the rules of evidence.

Your expert witness can testify to inadmissible facts generally and specifically. And to make the rules work for you, make sure they always testify generally to maximize their chances of getting specific.

The practice of law (let’s differentiate from the law itself) is justice poker. Wins come from a simple mistake ratio — yours to theirs. If you have fewer than opposing counsel, congratulations – you won. Fine print: a mistake can be taking the case or taking it trial in the first place.

Cross-examination is more than Wigmore’s tag as “beyond any doubt the greatest legal engine ever invented for the discovery of truth.” The most powerful artillery is useless without accurate, precise coordinates. Misdirect the cross, watch the mistakes multiply.

And expert witnesses can do just that. With Federal Rule of Evidence 703 and 705 working together, you can get the defense to bring inadmissible evidence into court — without a limiting instruction.

  1. The Rules and Rationales

Federal Rule of Evidence 703 is simple:

An expert may base an opinion on facts or data in the case that the expert has been made aware of or personally observed. If experts in the particular field would reasonably rely on those kinds of facts or data in forming an opinion on the subject, they need not be admissible for the opinion to be admitted. But if the facts or data would otherwise be inadmissible, the proponent of the opinion may disclose them to the jury only if their probative value in helping the jury evaluate the opinion substantially outweighs their prejudicial effect.

The first sentence makes the expert a courtroom unto himself, respecting his process of gathering evidence and factual data. Further, an expert can offer an opinion based on facts, theoretically, without any evidentiary support. And last, the expert can be a conduit for otherwise inadmissible facts under certain circumstances — namely, where those facts are vital to understanding the opinion and the jury’s comprehension of the opinion outweighs the prejudice those facts could cause a party opponent.

Federal Rule of Evidence 705 is simple:

Unless the court orders otherwise, an expert may state an opinion — and give the reasons for it — without first testifying to the underlying facts or data. But the expert may be required to disclose those facts or data on cross-examination.

Straight-ahead but still keeping on with the expert-as-court analogy. The expert may offer an opinion and its reasons without specifying the facts or data underlying that opinion. Of course, the second sentence renders the analogy imperfect by requiring the expert to produce such data on cross-examination. Superficially — when would an expert rely on data supporting an opposite conclusion to theirs? Let’s refrain from answering and acknowledge that we would all be surprised at what happens in the reality of court. Exceptions prove the rule, though.

Moving on, the interplay between FRE 703 and 705 is slippery.

Returning to the micro-court analogy, an expert operates like a courtroom. A trial (1) ascertains a set of facts and (2) applies a principle to resolve a dispute regarding those facts. An expert (1) ascertains a set of facts and (2) applies a principle to resolve a dispute regarding those facts. And the rationale behind both rules is to give the expert freedom to pursue his personal process. Limiting an expert only to facts that the expert has direct awareness of would be an Achilles tendon cut. An expert needs access to the requisite data to apply whatever principle the court has called him to adduce.

The practical effect here is that, even without disclosing particulars of the court-verboten facts, the expert can essentially testify generally about them. For example, an expert psychologist bases his opinion that a party is insane on medical records — admissible — and interviews with a party’s friends and family — inadmissible hearsay. The expert witness can testify that he or she based their opinion on the interviews without disclosing the content of those interviews. While the content remains outside of court, enough is within court to support an inference about the content.

The hail mary option is to have the expert outright testify as to the inadmissible facts, hoping that the court admits it. The court must find that the value of these facts in helping the juror understand the expert’s testimony is higher than the prejudice a party opponent will suffer from those facts. The chance of success is low, and the court will accompany the testimony with a limiting instruction.

But FRE 705 renders the foregoing hail mary option unnecessary. FRE 705 allows an expert to state his or her opinion and the reasons supporting without testifying about the specific facts or data. However, a party can elicit those facts and that data via cross-examination. And this is where justice poker begins.

2. Training the Defendant’s Crosshairs on the Defendant

The advisory committee’s notes to the 2000 amendments to FRE 703 sum up our strategic consideration:

Nothing in this Rule restricts the presentation of underlying expert facts or data when offered by an adverse party. See Rule 705. Of course, an adversary’s attack on an expert’s basis will often open the door to a proponent’s rebuttal with information that was reasonably relied upon by the expert, even if that information would not have been discloseable initially under the balancing test provided by this amendment. Moreover, in some circumstances the proponent might wish to disclose information that is relied upon by the expert in order to “remove the sting” from the opponent’s anticipated attack, and thereby prevent the jury from drawing an unfair negative inference. The trial court should take this consideration into account in applying the balancing test provided by this amendment.

Consequently, the optimal play here is to always have the expert testify under FRE 705 as to their opinion and the general nature of any inadmissible basis. If the defense elicits otherwise inadmissible evidence from cross-examination, then the balancing test has a much higher chance of tipping toward counsel introducing the entirety of that evidence.

This strategy is low risk and high reward; it puts the defense in its proper place — on the defensive. The inadmissible facts surrounded by the expert’s testimony are near impregnable. To mount a successful assault on the facts themselves, defense counsel will have to attack the expert’s testimony itself; and if the expert has survived a Daubert challenge…good luck.

Either way, you win. If the defense forces the expert to reveal, then you can reveal the entirety of the contents — regardless of veracity, the jury has now heard these facts. Even if alone, the facts themselves are weak, weak facts strung together by a story become more powerful than the sum of their parts. Old Chief v. United States taught us all that.


So consult FRE 703 and FRE 705 to execute this optimal play and minimize the mistakes you make in expert testimony. At Expertpays, we believe that experts should be available whenever, wherever the world needs them, which is why we bankroll them for you zero-interest and zero up front cost. We are here to give you the tools to win, because you only pay when you win.