MaxDiff (Maximum Difference Scaling)

Main aspects

  • MaxDiff is used to prioritise a large set of items - messages, attributes, needs etc...
  • Traditionally, people would be asked to rate the importance of each item on some scale. However, the resultant average scores tend to be rather 'flat', with poor differentiation between the items and also between different groups of people.
  • MaxDiff avoids the use of a scale by presenting a series of subsets of the entire set of items and asking people to indicate which item they consider most important and which least, in the context of each subset. Thus they complete a series of mini trade-off exercises.
  • A special design is used to ensure that all items are covered across all subsets in a balanced way. 20 items could be covered by 10 subsets, each of 5 items, for example.
  • The data are analysed to derive the importance of each item for each person. Results typically show much better differentiation than with the straight rating method.