ASTM D4855-97(2002) (R1997)

1.1 This practice provides a procedure for evaluating and comparing test methods under controlled conditions using the same materials tested during the same time span. The practice describes how to obtain and compare estimates on precision, sensitivity, and bias.

1.2 This practice covers the following topics:

Task groups developing a test method frequently find themselves with two or more alternative procedures that must be compared. Three common situations are:

4.1.1 Two or more new test methods may have been proposed to measure a property for which there is no existing method.

4.1.2 A new test method may have been suggested to replace an existing test method.

4.1.3 Two or more existing test methods may overlap in their scopes so that one should be chosen over the other.

The selection of one test method in preference to another is not simply a statistical choice. There are many other aspects of two test methods that should be considered, which may have an influence (on the engineering judgment of the task group) equal to or greater than the statistical evidence. Some of these characteristics are discussed in Section 6.