In economics, hedonic regression, also sometimes called hedonic demand theory, is a revealed preference method for estimating demand or value of a characteristic of a differentiated good. It decomposes the item being researched into its constituent characteristics and obtains estimates of the contributory value for each. This requires that the composite good (the item being researched and valued) can be reduced to its constituent parts and that those resulting parts are in some way valued by the market. Hedonic models are most commonly estimated using regression analysis, although some more generalized models such as sales adjustment grids are special cases which do not.