Standard Practice for Conducting Ruggedness Tests

Importancia y uso:

4.1 A ruggedness test is a special application of a statistically designed experiment that makes changes in the test method variables, called factors, and then calculates the subsequent effect of those changes upon the test results. Factors are features of the test method or of the laboratory environment that are known to vary across laboratories and are subject to control by the test method.

4.1.1 Statistical design enables more efficient and cost-effective determination of the factor effects than would be achieved if separate experiments were carried out for each factor. The proposed designs are easy to use in developing the information needed for evaluating quantitative test methods.

4.2 In ruggedness testing, the two levels (settings) for each factor are chosen to use moderate separations between the high and low settings. In general, if there is an underlying difference between the levels, then the size of effects will increase with increased separation between the high and low settings of the factors. A run is an execution of the test method under prescribed settings of each of the factors under study. A ruggedness test consists of a set of runs.

4.3 A ruggedness test is usually conducted within a single laboratory on uniform material, so that the effects of changing only the factors are measured. The results may then be used to assist in determining the degree of control required of factors described in the test method.

4.4 Ruggedness testing should precede an interlaboratory (round robin) study to correct any deficiencies in the test method and may also be part of the validation phase of developing a standard test method as described in Guide E1488.

4.5 This standard discusses design and analysis of ruggedness testing in Section 5 and contains an example of a basic eight run design. Some caution must be used in interpretation of results, since interaction effects may be present. These effects are present when a factor effect changes with the level of other factors in the experimental design. If it is thought that there may be interaction between variables then additional testing of the basic design is necessary. This is discussed in Section 6. In addition, Annex A3 presents estimates of precision of factor effects when run settings are replicated. An example of a twelve run design is shown in Appendix X1. Annex A1 and Annex A2 provide supplemental information.

Subcomité:

E11.20

Referida por:

E1601-19, E1323-15R20, E3414-23, E1488-23, E0456-13AR22E01, E1601-19, F2394-07R22, D3670-91R22, D3670-91R22, E1323-15R20, E3098-24, E1488-23, G0156-24, C1067-20, E2653-23, D7778-15R22E01, E3097-23, E0691-23, E0691-23, D8272-19, D2777-21

Volúmen:

14.01

Número ICS:

19.020 (Test conditions and procedures in general)

Palabras clave:

foldover; fractional factorial design; half-normal plot; Plackett-Burman; ruggedness; screening design;