A delay expert report gets torn apart for one reason more than any other.

Not methodology.

Not analysis.

Assumptions.

I’ve reviewed reports where the analysis was technically sound.

The method was appropriate.

The schedule logic was defensible.

But buried in the appendices or worse, not disclosed at all — were assumptions that nobody had validated.

The as-planned schedule was assumed to be achievable.

The as-built records were assumed to be complete.

The cause of a delay was assumed without independent verification.

And when those assumptions get challenged in cross-examination, the whole report collapses.

Because the conclusion is only as strong as what it’s built on.

Here’s what separates an expert report that holds up from one that doesn’t:

✔ Every assumption is named. Not hidden. Named, documented, and explained.

✔ The methodology follows the contract. Not the other way around. You don’t choose a method and then fit the contract to it. Contract first, method second.

✔ The records drive the analysis. Contemporary records. Not reconstructed narratives. Not “we believe this is what happened.” What the documents show.

✔ The analysis is reproducible. If someone else ran it with the same inputs, they’d get the same answer. That’s defensibility.

A good expert report isn’t just technically correct.

It’s built to survive the hardest question the other side can ask.

What question would break yours?