Having been closely involved with such a project in a large international school in the Middle East, I can confirm that self-evaluation, subsequently ratified by an external agency, can be an excellent professional development tool.
Properly handled, the accreditation process is a motivating, and non-threatening, instrument which involves every member of the community. By the judicious staffing of sub-committees, staff can be given the chance to investigate areas of school life when they might otherwise have taken them for granted.
As a follow-up to a detailed self-evaluation, ECIS will send a team of experienced colleagues from other schools to "compare notes". The whole process is at once threat-free but very significant to the school, and extremely productive in terms of staff involvement. The brief of the visiting team is not to criticise, but to find out if the school is producing the educational goods it claims to by its own evaluation, and then of course to report back to the school.
There are many ways of assessing a school's performance. The ECIS protocol is a welcome and effective alternative to current inspection methods. Its methods could apply as well to UK-maintained schools as to the overseas international sector.
Headteacher, The British International School of Al Khobar, Saudi Arabia