As a result, when several different methods agree, this is strong evidence that "none" of the methods are in error and the conclusion is correct. This is because of a greatly reduced likelihood of errors: for a consensus estimate from multiple measurements to be wrong, the errors would have to be similar for all samples and all methods of measurement, which is extremely unlikely. Random errors will tend to cancel out as more measurements are made, due to regression to the mean; systematic errors will be detected by differences between the measurements (and will also tend to cancel out since the direction of the error will still be random). This is how scientific theories reach high confidence – over time, they build up a large degree of evidence which converges on the same conclusion.