§ 40.425 Rule 705. Disclosure of fact or data underlying expert opinion

Here's what this rule means in everyday terms.

When an expert witness testifies in court, they can share their opinion right away without first explaining every fact or piece of data that led them to that conclusion. For example, a doctor testifying about someone's injuries can state their medical opinion without walking through every test result and detail first. This makes it faster and easier for experts to give their opinions during the main part of their testimony.

However, the judge can require more upfront explanation if needed. Also, once the other side gets a chance to cross-examine the expert, they can push for those underlying facts and data. This means a lawyer questioning the expert can ask "why do you think that?" and demand specifics about what information the expert relied on.

In short, this rule lets experts get to the point quickly during direct testimony, but it does not let them hide their reasoning forever. The other side still gets a fair chance to dig into the details and test whether the expert's opinion actually holds up.