1) ideology, generally religious ideology, because a school's "educational philosophy" is never shared by the majority of the teachers, regardless of what it is (and many won't even be clear on what it is)
I see your point, but I'd argue that this concern is an administrative concern, and a sign that your past principals were unqualified, ineffective, or both on the business side of the equation. Educators are educators, administrators are administrators. Too many private schools are run by educators, only, when both business and education credentials are needed.
I have three remedies to your concern, assuming someone with relevant business training is at the helm of administrative decisions:
1. Pay teachers more, so that the cost of not adhering to the school teaching ethos (being fired) is painful and the reward of staying is strongly appealing.
2. Conduct multi-stage interviews culminating in an evaluation center simulation to tease out how teachers act in challenging situations. These are expensive but so worthwhile if choosing the right talent is valued by management.
3. Set SMART goals with specific outputs tied to the school philosophy in the employment contract, with transparent measurement and action.
And a bonus strategy: spike the staff room Kool-Aid. Just kidding!
