title: The area under the disease progress stairs: calculation, advantage, and application.
abstract: The area under the disease progress curve (AUDPC) is frequently used to combine multiple observations of disease progress into a single value. However, our analysis shows that this approach severely underestimates the effect of the first and last observation. To get a better estimate of disease progress, we have developed a new formula termed the area under the disease progress stairs (AUDPS). The AUDPS approach improves the estimation of disease progress by giving a weight closer to optimal to the first and last observations. Analysis of real data indicates that AUDPS outperforms AUDPC in most of the tested trials and may be less precise than AUDPC only when assessments in the first or last observations have a comparatively large variance. We propose using AUDPS and its standardized (sAUDPS) and relative (rAUDPS) forms when combining multiple observations from disease progress experiments into a single value.
authors: U.S. Department of Agriculture-Agricultural Research Service, Crop Improvement and Protection Research Unit, 1636 East Alisal Street, Salinas, CA 93905, USA. ivan.simko@ars.usda.gov
authors: Ivan
authors: I
authors: Simko
authors: Hans-Peter
authors: HP
authors: Piepho
mesh_terms: D000704:Analysis of Variance; D003627:Data Interpretation, Statistical; D060467:Disease Resistance; D005659:Fungicides, Industrial / Q000627:therapeutic use; D054884:Host-Pathogen Interactions; D008954:Models, Biological; D015233:Models, Statistical; D010935:Plant Diseases / Q000382:microbiology / Q000469:parasitology / Q000628:therapy; D013997:Time Factors
chemical_list: D005659:Fungicides, Industrial