Failure censoring is useful for:
· Testing
lower percentiles - For
any percentile, increasing the test duration improves the precision of
your estimate. However, you will see little improvement in precision when
you run a test far beyond the estimated percentile. For example, if you
estimate the 10th percentile, you obtain important gains in precision
by running the test until around 15% of the units fail, but little improvement
by running the test longer. In fact, running the test beyond 15% of the
units failing could bias your estimate of the 10th percentile.
· Replacing
test units - If you have
a limited number of test positions, you can use failure censoring to determine
when to replace unfailed units. For example, if you want to estimate the
10th percentile, but can only test 5 units at a time, you may want to
replace all 5 units after the first failure in each group. In this case,
you are failure-censoring when 20% of the units in each group have failed.
Failure Censoring