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Title: AUDPC and AUDPS: What is the Difference?

Author
item Simko, Ivan
item PIEPHO, HANS-PETER - University Of Hohenheim

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/7/2012
Publication Date: 7/1/2012
Citation: Simko, I., Piepho, H. 2012. AUDPC and AUDPS: What is the Difference? Phytopathology. 102:S4.110.

Interpretive Summary: To combine multiple observations of a disease progress into a single value, the Area Under the Disease Progress Curve (AUDPC) is frequently used. However, our analyses show that this approach gives a smaller weight to the first and the last observation. Therefore, we have developed the formula termed the Area Under the Disease Progress Stairs (AUDPS) that combines repeated observations of the disease progress into a single value. The AUDPS has the same conceptual basis as the Area Under the Disease Progress Curve (AUDPC), however the AUDPS approach gives the two observations the same weight as to all other observations (if all observations are performed at regular intervals). Because of this difference, AUDPS scales linearly with the duration of the disease while AUDPC does not. Empirical evaluations suggest that AUDPS outperforms AUDPC in terms of precision in most of the tested trials when statistics from one-way ANOVA are compared; and that this weighting scheme often improves the precision of disease assessment.

Technical Abstract: We have developed the formula termed the Area Under the Disease Progress Stairs (AUDPS) that combines repeated observations of the disease progress into a single value. The AUDPS has the same conceptual basis as the Area Under the Disease Progress Curve (AUDPC), however the two approaches differ in the weight that is given to the first and the last observations. While AUDPC gives less weight to the first and the last observations, AUDPS approach gives the two observations the same weight as to all other observations (if all observations are performed at regular intervals). Our empirical investigations indicate that this weighting scheme often improves the precision of disease assessment. Because of this difference, AUDPS scales linearly with the duration of the disease while AUDPC does not. Empirical evaluations suggest that AUDPS outperforms AUDPC in terms of precision in most of the tested trials when statistics from one-way ANOVA are compared.