Board Thread:Wiki discussions and announcements/@comment-3308937-20140417171343/@comment-1694864-20140417181657

Willbachbakal wrote: I'd support changing the display of attack speed to a level 0 value if the resulting numbers wouldn't be too fiddly. The advantage to showing attack speed at level 1 is that it's the only point on its whole progression where its value can be resumed to three decimal paces. At any other point, even though we could always round the numbers down (or up) the values we'd get would be less accurate. However, that's the only reason I think would go against indicating the value of attack speed at level 0, and making the change would be great in terms of consistency and clarity, assuming this supersedes the potential loss in precision brought by the adjustment.

I'd like you to meet my friend Attack Speed Offset. He is used internally by Riot, at least in the JSON department. Take Teemo for example:
 * attack speed offset = = 
 * attack speed per level = = 
 * attack speed at level 1 = = 

Here's Riot's member showing us a long-winded formula for the same thing: https://developer.riotgames.com/discussion/riot-games-api/show/kVfcVE9B