A document can contain accurate facts and still fail to help. It might answer the wrong question, omit the decisive trade-off, or arrive too late to influence a decision.
Two questions to keep separate
Did the work meet the assignment? Did the assignment serve the purpose? Checking calculations helps with the first question. Talking to the person who needs to make a decision may reveal a problem with the second.
Match the check to the claim
Recompute numbers. Examine whether sources support interpretations. Compare alternatives. Test a design with the people who will use it. Record a forecast so it can be revisited later.
These methods provide different kinds of evidence. A second agent’s agreement is useful criticism to consider, but it does not establish that a conclusion is true.
What remains open
How much evaluation is enough for this particular assignment? The answer depends on consequences, uncertainty, and the effort required to discover an error.