A trial judge should have barred as a net opinion an expert witness's testimony that legal malpractice must have been to blame for a low damages award in a suit against Prudential, a New Jersey appeals court ruled on Monday.

Overturning a $1.6 million judgment in the malpractice case, the Appellate Division also found error in the failure to instruct the jury that the plaintiff lawyer's decision to present damages to an arbitration panel as a lump sum could be deemed an "exercise of judgment" rather than a breach of the standard of care.