How are ranks actually calculated?

For basic context, I have been playing deadlock since the open beta opened up a few months ago. Over the last week, I went on a 19 game win streak, having top damage and top objective damage in 80% of the games. My top 3 characters used all have near 70%+ win rates. With all that, during this win streak I only went from arcanist 2 to arcanist 4. And then after loosing 2 games I was ranked back down to arcanist 3.

Clearly personal performance does not account towards rank, and apparently winning 19 games in a row isn’t doing much either?

So my question here is basically, how does the ranking system work. What does the game like to see/ dislike?