The results show that the fixed effects of global position are significant for both measures in both corpora: Entropy in Switchboard, β = 4.2 × 10 −3 , p < 0.001; normalized entropy in Switchboard, β = 5.9 × 10 −4 , p < 0.001; entropy in BNC, β = 1.5 × 10 −2 , p < 0.001; normalized entropy in BNC, β = 1.4 × 10 −3 , p < 0.001).
since the curves of Switchboard seem flat after a boost in the early phase (between 0 to 5 in global position), we fit extra models to examine whether the entropy increase for global positions larger than 10 is significant.