This weighted ranking is realised thanks to the IMDB formula below:

Rank = (N / (N+Nm)) * M + (Nm / (N+Nm)) * Mf

M = average for the title
N = number of votes for the title
Nm = minimum of votes required to be listed
Mf = the mean vote across the whole report

To be listed in this top sci-fi rank a movie or a series must get a minimum of 5 reviews (votes).