I was doing keyword research on my Facebook account and pasted the results in my partner's account later. With exactly the same targeting, he got 298K in audience estimate while I was only at 105K. Does this happen a lot? What are the implications?
The estimated reach/audience aren't account specific. You probably just had some option selected in one account and not in the other. E.g. Male only, or more likely a language difference.
Nope...trust me, we quadruple-checked because we were both surprised at the difference. It was the same list of keywords...Same country....one language....male only, single, 26-35 demographic with exact age match.
Hmm just tried myself, switching between two accounts caused my estimated reach for a few random demos to change by a few hundred people, although this is with an overall reach of 100,000 to 1.5 million. In the API platform I use I switched back and forth dozens of times and the small variation didn't correlate to any account, it just seemed to be two slightly different predictions of estimated reach that were being displayed. Though the difference you're describing seems bizarre.
Try changing your targeting by one option then change back, e.g. go male -> female -> male -> female and see if the results change, or untick single then retick it.
Thanks for the replies man, appreciated.