Uniformity test of bias when the reference value contains experimental error

The uniformity test of biases for analytical methods must address uncertain ties in the reference method. If the uncertainty associated with the estima tes of true values is significant but ignored in the test of bias equality, the type I error can exceed the prespecified error rate. In general, when biases at each concentration level are confounded with a random component ( confounding bias), the usual test of bias equality tests the uniformity of the combined bias, rather than the uniformity of fixed bias-the bias withou t the random component. Based on a confounding model that takes both the fi xed and the confounding biases into account, the actual type I error rate o f the uniformity test can be calculated. To eliminate the impact of confoun ding bias on the uniformity test of fixed biases, a new F'-test is proposed . The new F'-test is simply adding a correction factor to the conventional, F-test. The correction factor is directly related to the uncertainty assoc iated with the estimates of true values. A simulation study is conducted to show that the proposed test can bring the type I error rate down to the pr especified level. Data from two aldehyde methods are used to demonstrate ho w the proposed F'-test works. Recommendations on optimal sample allocation are also provided.