Polarized score distributions in music ratings and the emergence of popular artists

According to our statistical analysis based on the datasets provided by Yahoo!, most users have a favored score which is used most frequently in their music ratings. We call the frequency of a user´s most favored score the polarization ratio since the rating distributions depict apparent polarizations: 66.99% of the total users have the frequency larger than 0.5; while 80.37% of the total users´ most favored score is either 0 or 90. Furthermore, our statistical analysis shows that the rating score distributions are highly polarized for average raters as well as so called heavy raters regardless of the total times a user rated. Finally, our analysis of the ratings on four categories of music items reveals the emergence of popular artists, which signifies the importance of the introduction of a user´s most favored score and its frequency in quantitative descriptions of human behavior in music ratings.