Clutch slipping

My sons 1995 escort has a serious clutch slipping problem.We replaced the clutch about 20,000 miles ago along with the pressure plate and throw out bearing and cannot understand why we are having this problem. The car is not abused and I,m wondering what will make a clutch slip other then being "worn out". Any Ideas!!!

the flywheel should have been reserfust. because i bet it was blue from slipping before you had clutch and presure plate put in.

I once had an oil leak on my 94... was leaking from the main seal right onto the clutch and causing it to slip.
It sounds as if your parts aren't worn, so I wonder if you might have some leakage. Take off the inspection cover at the bottom of the tranny and have a look up in there.
If you find any signs of leakage in that area then you will likely need to pull it apart. You may have some luck just cleaning up the clutch plate and repairing the leak, but replacing the clutch would be best (assuming it is getting oil on it).
Just a thought...