title: A cautionary note on applying scores in stratified data.
abstract: When rank tests are used to analyze stratified data, three methods for assigning scores to the observations have been proposed: (S) independently within each stratum (see Lehmann, 1975, Nonparametrics: Statistical Methods Based on Ranks; San Francisco: Holden-Day); (A) after aligning the observations within each stratum and then pooling the aligned observations (Hodges and Lehmann, 1962, Annals of Mathematical Statistics 33, 482-497); and (P) after pooling the observations across all strata (that is, without alignment) (Mantel, 1963, Journal of the American Statistical Association 58, 690-700; Mantel and Ciminera, 1979, Cancer Research 39, 4308-4315). Test statistics are formed for each method by combining the stratum-specific linear rank tests using the assigned scores. We show that method P is sensitive to the score function used in the case of two moderately sized strata. In general, we recommend methods S and A for use with moderate to large-sized strata.
authors.affiliation: National Eye Institute, Division of Biometry and Epidemiology, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: M J
authors.initials: MJ
authors.lastname: Podgor
authors.forename: J L
authors.initials: JL
authors.lastname: Gastwirth
mesh_terms: D001699:Biometry / Q000379:methods*; D002352:Carrier Proteins / Q000097:blood; D005260:Female; D006023:Glycoproteins / Q000097:blood; D006801:Humans; D008049:Lipase; D008297:Male; D008433:Mathematics; D015233:Models, Statistical; D010179:Pancreas; D010190:Pancreatic Neoplasms / Q000097:blood; D012016:Reference Values
chemical_list: D002352:Carrier Proteins; D006023:Glycoproteins; C054621:CEL protein, human; D008049:Lipase