An expert opinion is worthless and inadmissible without adequate factual support. Although there may be disagreement as to what is adequate factual support, having some factual support is necessary. As the title implies, the particular expert in this post has previously encountered this issue.
In Millan v. Cardenas Mkts., Inc. the defendant moved to expert Plaintiff’s liability expert, Gary Presswood. He offered four opinions:
(1) water on the floor is a hazard;
(2) the floor where Millan fell likely had low slip-resistance qualities;
(3) “there is insufficient evidence to establish a critical risk management procedure at the facility in order to secure adequate safety for pedestrians”; and
(4) there is no evidence that Millan contributed to the event.
“It is undisputed that Presswood did not inspect the premises or test Cardenas’s floor before he prepared his report.” The court first addressed the “low slip-resistance qualities” opinion and noted “Presswood has been previously excluded from testifying at trial in similar circumstances.” This was a reference to the case discussed in the prior post.
The gap between the data relied upon and Presswood’s opinion regarding slip-resistance is even wider in this case. Here, Presswood does not know the type of floor involved, let alone any other information about its attributes or condition. He offers no facts indicating that the floor where Millan fell is similar to or representative of the other floors he has inspected. He does not indicate that he knows whether the floor was smooth or textured. In short, Presswood’s opinion is not adequately tied to the facts of this case.
After excluding that opinion, the court addressed the other three opinions. To summarize, they were excluded “[b]ecause these issues fall within the common knowledge of laypersons, and Presswood has no greater or more specialized knowledge of these facts than the jurors will, Presswood’s opinions on these questions would not be helpful to the jury….”
 No. 2:16-cv-01549, 2017 U.S. Dist. LEXIS 145996, 2017 WL 3973033 (D. Nev. Sep. 8, 2017). Full disclosure, I represented the defendant.