Need a better rating system

Recently, as a political vendetta, people registered on IMDb and gave low rating Chhapaak to bring its rating down. Similarly, to counter this, people registered in to give high rating to Chhapaak to bring the rating back up. But, they were outnumbered.

This is truly an alarming situation. IMDb is respected the world over for providing a crowdsourced popular rating. However, this system is being misused by people who are politically inclined.

To counter this, provide an option where one can choose the aggregate rating by users who have been IMDb users for a selectable duration. e.g. I would like to see rating by users who are members of IMDB for one year or more. You could also give 3 separate ratings :

Greenhorns - aggregate rating by users who are less than a month old on IMDb
Silvers - aggregate rating by users who are more than a month old but less than a year old
Golds - aggregate rating by users who are more than a year old.

Perhaps, by default you can give Golds rating.