Rolled Throughput Yield
(RTY) is a term used in Six
Sigma. It is the probability
that a unit can pass through a process without
defects. It is the product of the first
pass yields at each step:
RTY = y_{1} x y_{2}
x y_{3} x ………..y_{n}
where the y_{i} values are the
yields at each step before rework.
The argument is that the perceived yield
is misleading because it ignores the rework.
Management often do not realize, or measure.
the amount of rework that occurs within
a process and it can be extremely large.
Because of this it is sometimes known as
the 'hidden factory'. Consider an example:

Defects 
Scrap 
Rework 
Units 
DPU 
FPY 
RTY 
1 
10 
5 
5 
100 
0.100 
0.905 
0.905 
2 
12 
5 
7 
95 
0.126 
0.881 
0.797 
3 
8 
0 
8 
90 
0.089 
0.915 
0.730 
4 
10 
5 
5 
90 
0.111 
0.895 
0.653 
5 
5 
1 
4 
85 
0.059 
0.943 
0.616 
Totals 
45 


460 
0.485 

0.616 
Follow the link for other Six
Sigma Metrics. 