For the school, I use:
- The school's Search Associates profile
I use the profile mostly for salary information, which is in my experience never off by a lot (savings potential can be way off however), the size of the school, the number of local students (also frequently off due to local kids having foreign second passport which the school counts as international), and some other benefits information, and curriculum. All this info I will double check as well as possible through other sources once I get closer to shortlisting a school.
- Current or former colleagues, or colleagues of former colleagues, or former colleagues of current or former colleagues
The benefit of being an experienced IT is that you know a lot of people from previous schools, and I try to keep in touch. When I want to know more about a school, I ask my network if anyone has worked there, knows someone who has worked there, or someone who still works there.
- ISR reviews & the paid ISR forum
Sometimes very helpful, but I always assume reviews can be fake - either glowing reviews by admin, or a disgruntled teacher who was fired and wants to settle a score by making stuff up (in addition to some perhaps just complaints).
Leadership reviewing their own schools and themselves is usually easiest to spot, but I once saw a review about one of my past schools that was posted when I still worked there which was filled with blatant lies (about missing benefits, salary, admin never having taught, etc. - all demonstrably untrue) but it was written in very reasonable tone which can easily fool jobseekers into avoiding the school.
- Sometimes if I can't find a current staff member through my network, I will befriend one or two on Facebook to ask about the current state of affairs at the school. Schools also provide contact details of staff, but they might have been chosen to support the admin's narrative about the school. For the better schools, this is usually not the case though in my experience - I've only gotten honest answers so far.
For the city:
- Numbeo and Expatistan for cost of living information
Usually pretty accurate but in my experience the averages for some of the larger expenses (cars, rent, some others) can be a bit on the high side. Great resource though.
- I 'drive' through the city using Google Streetview (of available for that city), and look a t a lot of pictures shown in Google Maps when you click on the name of a city or neighborhood.
for reports on how it is to live in a city as an expat. Most of the contributors are (married to) US diplomats though, so you have to keep that in mind. They also answer questions about the international schools in that city, which is sometimes useful. They have a separate section on ISs: https://www.talesmag.com/real-school-reports
but that is far from complete and is sometimes also just a single parent that had a bad experience which is not representative for the school.
- Friends of friends.
- If still not sure about a city, I join an Facebook group for expats in that city, and ask some questions there.
I think that's about it.
If it's a direct and cheap flight away, you can fly there during the October or Christmas break for a holiday to do some research on the ground, and ask for a tour of the school.