Data management in olfaction studies.

Problems arising in the collection of data in olfaction studies are discussed in relation with the specific nature of perception and description of odors. Olfactory data depend strongly on individual physiological differences, on measurement methods and on psychological factors. Classifications of odors are necessary to put some order in odor descriptions which are used in structure-odor relationships. Published classifications have been based on empirical, semi-empirical, or statistical approaches. In the last category data may be obtained using semantic descriptions, or profiles, or similarity estimations. Examples of each kind of classification are presented and discussed. The intensity data are most often threshold data. They also present a huge variability which makes it difficult to relate them to physicochemical properties. Data on thresholds and attempts to standardize them are presented and discussed.