When you provide a breath test sample in Oregon, the officer conducting the test is supposed to have you provide two samples. These two samples should be provided within a few minutes of each other. The Oregon Administrative Rules establish that the two samples must be within plus or minus ten percent of their mean or the sample will be canceled as a “sample correlation failure.”
So, as an illustration: Two samples are provided and one is .192 and the other .180. To determine the mean, .192 + .180 = .372. Thus, the mean would be .372/2 = .186. Then, we must determine 10% of .186 rounded would be .019. This is the 10% in which the samples must be within to be determined to be valid breath test samples. Thus 186 + .019 = .205 and .186 – .019 = .167. Therefore, for the breath test result to be valid, the samples must fall within the range of .167 and .205.