In his book, An Astronaut’s Guide to Living on Earth (which is a fantastic read by the way), Chris Hadfield mentions that people in any environment are either a +1 or a -1 in that they either add to a team, or take from a team. 


Similarly to this, Todd Whitaker mentions asking the question ‘how hard would it be to find a teacher to do as good a job or better’, as a metric for teacher appraisal. Jimmy Casas takes it one step further and asks ‘would you recommend this person, or would you go and actively recruit them?’ 


Taking these ideas into consideration, when you rate yourself in a school, do you feel that you are adding to the team, maintaining the team, or taking from the team? One way to evaluate yourself is on a scale from -2 to +2. This is by no means a comprehensive model and it is not meant to label particular teachers, but rather a mental model to help evaluate how you perform as part of the school team.