Strong evidence that Tank Items > DPS items.
I just had a game where I pick Ashe for support and played her with CDR+Tank Items instead of normal DPS build.
We've been trailing for quite a while but once the core of Tank items was completed we started owning other team at full speed. Finally I end up doing more damage than AP Nidalee, Zed, and Varus with ONLY ONE dps item - FROZEN MALET .
We managed to overcome 12k deficit and beat the game.
Opposing team had Ornn which was build as tank. Guess what ? Ornn was 3rd in damage without any normal damage items at all.