Abstract: A method of testing for the presence of faults in digital logic circuits is described. The method involves re-ordering a number of test vectors for testing digital circuits by selecting faults at random from an original fault list to form a sample fault list FN and then forming a vector set TN?1 and then simulating the vector set TN?1 against the fault list FN. Any vector from the set TN?1 which does not detect any fault is discarded and the remaining vectors are saved as vector set TN. The method steps are repeated N times (with N having a value of 1 to M. Duplicated vector patterns in each vector set are removed and then the final vector set is initialized to produce a final vector set TF.