Top 8 most active users in MovieLens data set and statistical analysis results with paired t-test.

The effect size is calculated as (Measurement|t = 0 − Measurement|t = 200)/standard.dev. Bold means significance, and ES means the effect size. Filter bias has a consistently significant and sizable effect on the three measurements across all 8 users. Random selection has less impact on the boundary shift and blind spot. However it significantly decreases the inequality. Active learning aims to help learn correct boundary, therefore it highly depends on the initial data points. Active learning affects points close to the boundary, thus it has limited effects overall.