Which ADC has the highest damage output assuming....
that they get to full build? Which ADC has the highest raw damage output endgame?
My vote would be either
or
but I'm not sure
that they get to full build? Which ADC has the highest raw damage output endgame?
My vote would be either
or
but I'm not sure
Pretty much however, I would put tristana in there over vayne. Yeah vayne's damage is high, especially with the true damage, but tristana can destroy an entire team with her late game aoe damage and attack speed buff.
But of those I think it would be kog'maw because that is who team liquid typically built their protect the adc comps around, but I'm not really sure.

I forgot about draven.
depends on enemy's armor health and mr and their builds
the answer is always 
Without a doubt raw damage and sustained damage goes to Draven
I think tristana, she has the best of both worlds for an ADC by having insane auto attack damage and ability damage.
late game trist instakills almost anything
single target reliable would be in this order:

multi target would be in this:

and single target mechanics aside is
assuming he catches all his axes.
the highest burst in my experience though:

as late game their combo will kill the other adcs before they get a chance to react. however....
can kill any adc with one to two axes depending on build come late game if they haven't built a GA or armor defensive item. assuming he crits. his damage in terms of pure burst from autos is unrivaled and unmatched. It is unreliable but strong as all hell.
Still feel the best adcs are
for their pure damage.