A: The extent of investigation depends on the type of claim. For example, auto accidents usually need some investigation, but not as much as medical malpractice or products liability claims. Product and medical malpractice claims usually require review by highly paid experts. Medical malpractice and products liability experts usually need to review documents and other materials before they can give their opinions. The attorney gathers the paperwork or other materials to be reviewed by the expert. This investigation takes time and money. Investigations in medical malpractice and products liability cases can take weeks or months.