Every campaign has two polls. One is a working document. The other is a press release.
The real internal has a universe definition — who they're calling, how they built the likely-voter screen, what turnout model they're using and why. It has a margin of error that actually reflects the sample size, not the one that sounds better in a quote. It has crosstabs: age, education, geography, sometimes media market. Those crosstabs are why they ran the poll. The top-line number tells you where you stand. The crosstabs tell you where to spend the next $800K and which persuasion windows are still open. That document does not leave the campaign. It goes to the candidate, the campaign manager, maybe the media consultant. It is a decision tool.
What gets released is not that document. It is a subset of that document, selected for a specific purpose. To move donors off the sideline. To give the press a number that fits a narrative they were already writing. To push the opponent into a defensive posture, spend money in a market they didn't plan to defend, or respond publicly in a way that validates the frame. The crosstabs that show a problem? Not in the release. The likely-voter screen that assumes a turnout model the campaign privately thinks is optimistic? Not mentioned.
So when a campaign drops a poll showing them up 6, the useful question isn't whether the number is accurate. It's why they decided to put it out right now. That answer tells you more about the race than the number does.