Being declared an "expert" means that the individual has some technical knowledge that might be helpful to the trier of fact.
"Beyond the ken of a juror" is the typical standard. A lay witness may testify only to what can be rationally perceived by the five classical senses. Any other knowledge must be attested to by an expert.
There are often almost always dueling experts who come to opposite conclusions.
Expert testimony in court is bought and paid for. That means you get almost nothing by cross examining your opponent's expert. The expert will have been well briefed by his counsel on the essential premises of the argument and will expend considerable effort avoiding conceding any of those basic premises on the stand.
Expert testimony from one side is almost always countered by a different expert from the other side. Hence, for example, in a personal injury lawsuit, the plaintiff's doctor will present his findings while a doctor working for the defendant will have the opportunity to examine the patient and draw his own medical conclusion, and present that to the jury. The jury must decide which of the two medical witnesses have presented the most compelling testimony. Naturally the plaintiff's doctor will offer the opinion that all of the plaintiff's injuries and ailments were proximally caused by the defendant's negligent actions, while the defendant's physician will testify in his equally estimable medical opinion that the plaintiff suffers from congenital and chronic ailments that were by no means the fault of the defendant.
It does not mean that the person is competent to speak about anything outside his area of expertise.
Which is what the witness did in this case. Irey suggested that his methods of examining typewritten text (not typsetting) in a convenience copy were valuable in determining whether the document had been forged. He has no expertise or experience in the detection of forgery, and referred to no instance by which his
ad hoc methods had been shown to have any probative value toward that end.
In short, you can't just walk into court as an expert witness and say, "I'm the expert and this is what I think."
It does not even mean that the court considers that person's expertise to be relevant. A court might provisionally listen to some testimony only to decide that it doesn't have anything to do with the issues in the case.
That's what happened here, and in the unmoderated thread I discussed this in a lengthy post analyzing the trial.
Orly Taitz' first witness Christopher Strunk was not presented as an expert, but his lay testimony was hearsay and thus inadmissible.
Her second witness was Felicito Papa, whom she presented as an expert but for whom she did not lay a foundation. Hence his testimony was also ruled inadmissible as unqualified.
Her third witness was Paul Irey, whom the court accepted provisionally as an expert on typesetting. In order to determine whether Irey's testimony was relevant and well-founded, the court has to hear it first. Hence the provisional acceptance. The court may very well, as it did in this case, determine after careful deliberation and reflection that the testimony was not qualified as expert for other reasons: in this case because Irey did not base his testimony on reputable science, and further because he testified on a subject (i.e., the forensic authentication of documents) for which no expertise had been claimed or demonstrated. It is quite proper for the trier of fact to determine, after hearing the testimony, that it should be given essentially no weight because it ultimately failed to adhere to all the federal rules of evidence governing expert testimony.
In my state, a court doesn't even have to declare a person to be an expert in any area. That's how little it matters.
Indiana has also apparently discarded the motions to qualify witnesses.