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A Threshold Model for Multiyear Genebank Data Based on Different Rating Scales
Author(s) -
Hartung K.,
Piepho H. P.
Publication year - 2005
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2004.0293
Subject(s) - rating scale , biology , scale (ratio) , ordinal data , statistics , ordinal scale , term (time) , plot (graphics) , mathematics , cartography , physics , quantum mechanics , geography
Genebanks routinely assess plant characteristics of accessions on an ordinal rating scale. A common problem with long‐term data is that the rating scale is changed from time to time. This paper proposes a method for joint analysis of data from different rating scales, assuming a threshold model with a common latent scale for the different rating systems. The method may be used to derive mean scores on any one of the rating scales based on a long‐term series of evaluation trials, as is illustrated using evaluation data on barley ( Hordeum spp.). While the proposed method was motivated by data problems encountered in genebanks, it may be of equal interest in other areas of application, such as plant breeding, where rating scales change across time.