I have never believed the oft-stated claim that the WT fudges their membership numbers. I have never doubted that they report the numbers that are received. The local counts of publishers, attendance at meetings and at conventions, is very diligently done so as to appear OCD. The reports of attendance and publishers that I see in the published reports are consistent with what I observe anecdotally.
I completely agree with slim, joe and lee on this issue.
In fact, the org's fairly meticulous counting of numbers is what is causing some of their reporting headaches of recent years. (I say only "fairly" meticulous, because inevitably some errors creep in at the local level, eg: how individual publishers choose to count their hours for their reports - no longer applicable from now - but generally the org are sticklers for collecting numbers.)
However, while I broadly believe the raw numbers, those figures do of course tell (or hide) a lot more.
For example, note what the GB used to report on, but no longer do. And the figures they used to break down that they now aggregate. Also, they leave out some figures, such as how many are disfellowshipped or choose to disassociate each year. And they leave out other context, like the facts stated by luckynedpepper.
Notice, for instance, that there is no mention in the 'highlights' of how many Memorial partakers there were in 2023...