Again, Knowledgebase. One would think that GAAP was the official number and non-GAAP the fiddled with number, but over the years companies have been mandated to include thing in GAAP which really don’t have to do with the on-going operation of the company. So, we go to non-GAAP where the company will have taken those out as a better representation of how the company is actually doing as its business. Of course, since there are no standards for non-GAAP like there are for GAAP, this leaves us vulnerable to the company’s interpretation, but for grabbing a number it is still a better start. Ultimately, one might want to go in and add and subtract individual items to personal taste and philosophy, but that is a lot of work and provides no comparison to anyone else’s figure.
I would only add that most companies who report non-GAAP, for the sake of transparency also report a reconciliation to GAAP so you can very easily see what’s been added/subtracted from the GAAP numbers. If you think something is amiss, it’s very easy to change.
Of course this still does not stop management from playing games. That’s one of the reasons it’s important to listen or read the conference calls transcripts. If you reason to distrust management, invest elsewhere. There are too many good opportunities to risk you money on what might be flaky, distrustful management.