I don't think expert witnesses are supposed to be necessarily impartial and can't personally favor one side or the other winning a case. It's part of the legal process that attorneys go out and hunt for the best possible advocate for their side. Additionally, expert witnesses are often paid a fee for their time and effort involved in preparing for and appearing to testify on a case. If we want to talk about bias, it feels like accepting money from one side should be just as damning as having a familial connection.

To me, it feels like any potential bias should be disclosed in legal filings and argued by the other side of the case during the legal dispute, and the judge/jury should weigh this in whatever decision-making process they employ.

In closing, I'd say this. Preparing for a serious trial might cost tens of thousands of dollars or more. Do you really want to live in a world where you can't offer to help a family member or friend who asks for your help in a subject matter you know about?

Expert witnesses are pretty much never impartial. Each attorney picks their own witness subject to the judge's approval on professional qualifications. The attorney, not the judge, chooses the witnesses. They get paid to say what the defense attorney wants them to say or the plaintiff attorney wants them to say. A plaintiff expert witness who doesn't say what the attorney wants will soon be out of work or vice versa.

So you often get each side with a biased witnessess arguing the other biased witness is wrong.

>They get paid to say what the defense attorney wants them to say or the plaintiff attorney wants them to say.

Having done this sort of work... Sort of. We were picked in part because we had already publicly written about a case in a way that supported one side's position. (Obviously the side that reached out to us.) There was nothing in our report I didn't personally agree with.

I'd add that my understanding is that, while some people do a relatively large amount of expert witness work--we did not--the preference is that expert witnesses don't do this as a full-time gig where it becomes a matter of supporting what whoever paying them wants.