Why Expert Witnesses Disagree on the Same Evidence

You’re looking at 2 expert reports, and it seems like someone received the wrong spreadsheet because the reports don’t match.

Both experts reviewed the same documents, but one says that lost profits are $800,000 (USD), and the other says they’re $150,000.

That’s a huge gap, and you need to look into it before the case moves any further.

You’re probably going to look at their credentials and see who’s stronger because that’s the next logical step.

Then you’ll look to see which report seems more thorough.

Unfortunately, none of that will tell you why there’s such a big gap between these numbers, and ultimately, that’s the answer you want.

Before you decide which of these opinions holds up, you have to find why the difference is there, or you risk arguing over the final figure while the assumption that’s the reason behind it is unexamined.

Federal Rule 702 requires expert testimony to be based on sufficient facts/data. It needs to use reliable principles/methods, and the application of the same needs to be applied reliably. In DEC 2023, the rule was amended to clarify that the party presenting the expert must demonstrate admissibility requirements are satisfied. – United States Courts

Start With the Question Each Expert Answered

A regular witness is supposed to share what they know without giving their opinion.

In other words, cold, hard facts.

An expert witness, however, is expected to stay impartial but say what they think of the evidence if that evidence is within their area of expertise.

Basically, they’re supposed to state the facts, but also give their opinion on the evidence.

So, when you have 2 expert witnesses saying 2 different things when they should say the same, it’s a problem.

That big gap between 2 estimates has you go checking for math, but before you do that, try to figure out what each expert was supposed to work out.

You might be comparing figures that cover different things, which would be a colossal waste of time.

Let’s say there was a supplier dispute and you ask one expert how much profit your client lost after the deliveries stopped.

You ask another how much profit your client lost BECAUSE deliveries stopped.

The difference here is that these types of questions sound really close/similar.

But they aren’t identical.

The first asks about losses from a customer who left for an unrelated reason.

The second needs to account for exactly that.

It could be the same with dates and expenses.

One report could cover 6 months, the other could cover a whole year.

You might end up spending a whole afternoon trying to explain the gap before you notice that the reports don’t cover the same ground.

In short, before you go digging through papers, make sure that both experts were working on the same thing.

And if you find out they haven’t, then you’ve found the cause of the problem.

If you’re discussing an assignment with a firm that helps you find an expert witness, like Round Table Group, be as precise as possible when you start explaining what you need assessed/analyzed.

Why the Same Records Could Produce Different Opinions

Suppose you’ve given both experts the same assignment and you still wound up looking at different results.

Here’s why that might have happened.

Would Sales Have Fallen Without the Breach?

Your client wants to know what they would have earned if the deliveries didn’t stop, and even though you have last year’s sales, you can’t just assume that this year would be the same.

Maybe a big customer already said they’d buy less, and one expert took that email so seriously and lowered the forecast.

But the other expert looked at that customer’s buying history and figured that’s a bigger factor than the email.

And that’s how you end up looking at different estimates.

Does the Method Separate the Breach From Other Causes?

You’ve got sales figures from before the deliveries stopped and from after.

You subtract one from the other, and you have a clear drop.

Yet, you still don’t know how much belongs in the claim.

Also, perhaps your client increased the prices that spring, and one expert used the drop in sales without adjusting for that increase while the other tries to account for customers buying less at the higher price.

Does a Decline in Sales Establish What Caused It?

The month deliveries stopped, and the month the sales fell line up perfectly, but you still have to explain the connection.

If customers canceled orders because it wasn’t possible to deliver them on time, you can work with that.

But if all you have is lower monthly totals, there’s more checking to be done.

That’s also where the experts’ opinions may differ.

One thinks the records explain the drop, and the other wants more evidence before they blame the supplier.

Conclusion

This is a pretty tricky situation to be in, but there’s an explanation for it.

You just need to be patient and see what each expert worked on.

If their starting points differ, then you’ve got your answer.

If they don’t, dig, and then dig some more.

Whatever the reason, you need to find it and see which of the reports you can use for negotiations.

Otherwise, you’re taking a huge risk that’s more than likely to come back and bite you at the worst possible moment.