What does it mean, "They represent our best guess"?

Question

Two Navy admirals and Intelligence officer talking about the positions of Japanese naval forces:

Admiral Spruance: Layton, how reliable are these estimates of the Japanese positions?

Layton: They represent our best guess, based on the intelligence that we have.

Admiral Spruance: I can't plan around your guess.

Nimitz: I understand that we're asking the impossible, but we need you to be specific.

What does it mean, "They represent our best guess"?

What does "represent" refer to?

I found this line in the movie "Midway 2019".

Answer 1

"They" refers to the estimates.

An estimate is a rough calculation - one that perhaps does not factor in every detail that could be known, and often in the absence of all the facts. Yet an estimate normally does include some calculations and is the product of intelligent thinking. By contrast, a "guess" implies a little less knowledge and thinking.

As a midway point between the two, we sometimes use the idiom "an educated guess", which implies that some thought has gone into it but without perhaps as much calculation.

Your example shows the contrast between how people view an "estimate" and a "guess". The Admiral asks how accurate the estimates are... but is told they are in fact a "best guess". He responds that a "guess" is not sufficient to plan around.