Teacher’s Corner: The One-Sample Runs Test: A Category of Exception

The popular One-Sample Runs Test is used to identify a nonrandom pattern in a sequence of dichotomous elements. Although the test is generally effective in the identification of patterns, it is demonstrated to be incapable of signaling departures from randomness with run lengths of two. Further-more, with run lengths of two, increasing the sample size reduces the power of the test. Run lengths strictly of two, therefore, generate a unique category of anomaly in the test’s overall performance.