In an m-failure test plan, the reliability demonstration test is successful if no more than m failures occur. The most common m-failure tests are the 0-failure test (m=0) or the 1-failure test (m=1).
For example, suppose you are testing lawn mower motors using an m-failure test where m = 3. Your reliability test is successful if no more than 3 failures occur in n identical systems that are tested independently and are subject to the same testing duration. Should more than 3 failures occur, your reliability test fails and the system doesn't meet the reliability requirement that you want to prove.
|0-failure test plan||m-failure test plan (m>0)|
|Total test time||May reduce 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.|
|Practicality||Is not practical when you are likely to have at least one failure.|| May not be feasible for highly reliable units.
Has a better chance of passing than a 0-failure test when you have a marginally improved design.
|Verification of assumptions|| Does not let you verify the assumptions of the test design:
|| Lets you verify the assumptions of the test design. There are several assumptions that you should consider when using an m-failure test plan: