No, it's just based on the votes. The base priority is 0.5 and it's lowered or raised if the net votes are negative or positive.
The calculation isn't very smooth though - questions with 0 votes get priority 0.5, 1 vote = 0.75, 2 votes = 0.83, 4+ votes = 0.9+, and anything over 10+ votes is 0.95+ ie basically 1.0.
