Whenever a suite of statistical tests is applied to the same data, the chance of at least one “false positive” result is generally larger than the chance of a false positive for each individual test considered singly. This is called “multiplicity.” The tendency for multiplicity to increase the false positive rate is exacerbated when the tests are selected after examining the data. (For instance, if a forensic investigator notices that the results frequently end in 0 or 5, then decides for that reason to test whether the occurrence of 0 and 5 is surprising, the chance of a false positive increases substantially.)