How to asses employees performance using their data? I have some employees' data consisting of three variables - the name of the employee, a value denoting their positive behavior and a value denoting their negative behavior. 

How to score employees using this data with a 70% weight on negative behavior and a 30% weight on positive behavior?
Assuming that the values denoting positive and negative behaviors are both positive, you can set score as - 

score = -0.7*negative_behavior_value + 0.3*positive_behaviour_value