//ngambles- on VideoCoPilot
(pickwhip source value).valueAtTime(time - 1);
--This will get you a one second delay.
(pickwhip source value).valueAtTime(time - thisComp.frameDuration);
--This will get you a two second delay.
(pickwhip source value).valueAtTime(time -2+(thisComp.frameDuration));
--This will get you a one frame delay.
--If you have many layers that will be delayed it may be helpful
to use the 'index' value of each layer:
(pickwhip source value).valueAtTime(time - index * thisComp.frameDuration);
--Each layer will be delayed by one more frame as you move down the layer stack because the index value will be increasing by one each time.