As of Blizzcon in November there has been an announcement about drastic changes to the ranked system. With that in mind the game is still in beta and even the current ranked system is a mystery to many and ever changing. Below you will find the most important information about ranked currently and we will update this as the system changes.
In Hearthstone: Heroes of Warcraft there is currently no way to drop down in rank. As this game is meant to be more casual and as mentioned it is in beta so its meant more for testing. You win matches in ranked and move up a system of ranks: Journeyman, Copper, Bronze, Silver, Gold, Platinum, Diamond, Master, and Grandmaster. These ranks also generally have three stars attached to them. The more stars you have the higher the rank.
If you win more games in a row your rank goes up faster but many believe the win percentage plays a part of ranked which could be part of that. Losing games will not drop you down in the ranked system but will likely force you to win several games in a row to make up for those losses.
I can’t stress enough how infantile the ranked system is currently and how much is actually unknown or ever changing. A new ranked system write up will be put in once major changes go live.