Choosing Between a 0-Failure and an M-Failure Test
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A 0-failure test...

An m-failure test (m > 0)...

Usually reduces total test time for highly reliable items.

May reduce total test time if you can run the tests sequentially. For example, if you are testing 3 units in a 1-failure test and the first 2 units pass, you do not have to test the third.

Is more practical when failures are unlikely in a reasonable amount of time.

May not be feasible for highly reliable units.

Does not let you check the assumptions of the test design.

·    You cannot estimate the shape (Weibull distribution) or scale (other distributions) to compare it to the assumed value.

·    You can estimate the scale (Weibull or exponential distribution) or location (other distributions), but your estimate may be conservative.

Allows you to check the assumptions of the test design.

·    You can estimate the shape (Weibull distribution) or scale (other distributions) and compare it to the assumed value.

·    You can obtain a more accurate estimate of the scale (Weibull or exponential distribution) or location (other distributions).

Does not make sense when you are likely to have at least one failure.

Has a better chance of passing than a 0-failure test when you have a marginally improved design.