Geez, Mattelot. Syzzle may have spent some time explaining why she shouldn't have to answer your question... but she also answered your question. Seriously, just go look at the site she's been repeatedly linking.

Since you've yet to take the time to copy paste it into your address bar, it is a "DPS Calculator" that utilizes the Stone, Sky, Sea content in order to give classes the DPS expected to defeat a given dummy as well as the DPS they've done when they fail.

As this is a "document" that solely utilizes information obtainable through the game we can say that the author is Square Enix, the information is documented at that site, and the last revision is the end of the latest maintenance. The maintainer of the site itself is appearing to be anonymous but the source of the information is sound enough for that to be of minor importance. Here's a few more details as to the information it provides.

Dummy HP: This information is pulled from the game itself by reading its memory. Since this act is against the Terms of Service, I cannot tell you how this can be done and I shouldn't tell you who is credited for pulling the numbers.

DPS: It's a rather simple calculation. Damage Done/Time Spent = DPS. If a computer gets division wrong then we have bigger things to worry about than "where's the proof". For the record, I am a programmer by trade and can confirm that the code for these calculations is sound.

There is no guesswork in the site. It is just cold, hard, factual data. If we cannot trust a site like that then why are we even doing any math at all?