RE: SIP vs ROI

The overall direction you suggest, measure in dollars instead of time,
makes sense for lots of reasons. It seems similar to the Value At Risk
measurements that trading firms use to measure their exposure. A dollar
we spend today is at risk until the decision paid for by that dollar is
tested in the crucible of real use.
 
One thing I like about measuring in days is that it is independent of
project scale. I can compare a 10 person team with a 20 person team
directly.
 
At the end of Critical Chain, Goldratt suggests measuring investment in
"dollar days", the number of dollars times the number of days those
dollars are unavailable for other uses. He doesn't explain in any more
detail, though. Does anyone know what he's talking about?
 
Kent