How does riot decide where champion basic abilities go for q, w , and e?

When the riot champion creation/ rework team work on a champion, how do they decide what basic abilities are q, w, and e? Is it in ascending cool downs? Is it in the order that the abilities were first imagined? Or is it just random? Meaning why is yasuo's dash e instead of q? Or why is Zed's razor shrunken q and not e?

Would be cool if someone from the riot champion creation team answered this.