Don’t do it, unless … I start with the conclusion, so that my stand be clear from the outset. To volunteer your expertise into giving testimony in the courtroom runs against powerful negative incentives. Attorneys on the opposite side will do their utmost to destroy your credibility. They will hunt for dirt, for anything unsavory reflecting on your character and on your scientific integrity. During counterexamination, they will do their best to confront you with your own contradictions : they will get you to at least qualify your previous unambiguous assertions ; they will confront them with the written record, at some cost to your credibility ; any change of mind you may have had, in your published work, will be posted on the screen for everyone to see ; they will gleefully post sentences you have penned which contradict one another. In short, they will make you look like a fool.
They will have invested their enormous resources in preparing to counter your arguments, which they will have had ample time to anticipate in their substance. They will have gone through your publications with a fine comb, recording in their computer archives a very large number of statements of yours bearing on the matter to be discussed at the trial. They will be well-prepared to destroy each assertion you have ever made in print . They will show to the judges statements by authorities in the field, after making you admit publicly that indeed you regard Drs. X, Y, Z as leaders in the discipline. They will call their own experts to the stand, and those will testify under oath that your word is worthless. And the fiercest weapon in their arsenal of demolition will be your own contradictions : that he who has never self-contradicted cast the first stone …