Best-Worst Scaling (BWS), also called maximum difference scaling, was introduced by Jordan Louviere in 1987 and developed with Anthony Marley and colleagues. Rather than rating items on a scale or making pairwise comparisons, respondents identify the best and worst items in a subset. This yields more discriminating data than simple ratings and avoids many response biases.
Three Cases of BWS
Case 2 (profile): best/worst attributes of a product profile → attribute importance
Case 3 (multi-profile): best/worst profiles from a set → preference model
In Case 1 BWS, each respondent sees a subset (typically 4–5) of items and selects the best and worst. Across many subsets (designed using balanced incomplete block designs), the frequency of being chosen as best vs. worst provides an interval-scale value for each item. The data are typically analyzed using multinomial logit models, linking BWS to Thurstonian scaling and Luce's choice axiom.
Advantages
BWS provides more information per task than paired comparisons (which yield only one comparison per question) and avoids scale-use biases that plague Likert-type ratings. It has been widely applied in health economics (valuing health states), marketing (preference measurement), environmental economics (valuing ecosystem services), and cross-cultural research where response style differences make ratings problematic.