Matchmaking - And number of wins for that particular queue
https://support.riotgames.com/hc/en-us/articles/201752954-Matchmaking-Guide
If a player is queued alone, the strength is determined by his personal matchmaking rating (referred to as MMR from here on out) and number of wins for that particular queue.
So after how many win in ranked it is worth to create smurf ??
REALLY ????