This is a children's chapter book or possibly YA novel that I read in English in the USA around 1990. I read a few books of this general style, so I'm hoping that I am not conflating multiple books.
The story takes place in an all-boys (boarding?) high school that is introducing a lot of cutting-edge practices, including having a computer on-site and utilizing the latest research-driven, "ivory tower" educational practices that work well in theory but not in practice. One of these practices involves giving out personality tests that contain questions that the students find incomprehensible, but are supposedly going to be fed into the computer to optimize teacher performance or practice.
Several students get together and form a secret society to oppose these newfangled practices, calling themselves "The Committee". The Committee is non-violent but assists students with committing and evading punishment for school rule violations. This group is eventually banned, but the students secretly reform the remnants of their group as an alliance with students at the girls' school next door. This allows the boys to deny under interrogation that they are still members of the banned group, since they characterize the new (gender-inclusive) group to officially be a new entity with a new name.
Given that the installation of the computer is treated as a big thing, I suspect that the book is from the 1970's or early 1980's when a school getting "a computer" was actually a big thing as opposed to ordinary.
