 Measurement scales that represent magnitudes of intervals between properties, or even magnitudes of ratios between properties, are called cardinal scales. Although the discussion in the social sciences often merely distinguishes between ordinal and cardinal preference measures, it is important to further distinguish between interval and ratio scales among the latter, as these require different assumptions to hold. An interval scale allows for meaningful comparisons of differences (e.g. “43°C is as much hotter than 41 °C as 29°C is hotter than 27°C”). In addition, a ratio scale also allows for meaningful comparisons of ratios (e.g. “12m is twice as long as 6m”). Although there have been some attempts to measure preferences on a ratio scale (in particular, see Kahneman and Tversky’s (1979) Prospect Theory, which requires a natural zero point and thus a ratio scale), most efforts have focussed on measuring preferences on an interval scale. 