What should a recommendation letter highlight for a computer science major application?

For a computer science applicant, the strongest recommendation letters usually emphasize how you think, not just that you earn high grades.

A good letter should highlight problem-solving, logical reasoning, persistence with difficult material, and how you approach ambiguity when there is not one obvious answer. For CS, colleges also like evidence that you can debug, revise, and keep working when something fails.

The best teachers to ask are usually ones who can speak concretely about your intellectual habits. A math teacher, computer science teacher, physics teacher, or engineering teacher can be a strong choice if they have seen you tackle challenging work and can describe specific examples.

What helps most is specificity. A strong letter might mention that you asked unusually sharp questions, found efficient ways to solve problems, helped classmates understand concepts, built something beyond the assignment, or improved a project through multiple iterations.

It is also valuable if the letter shows qualities beyond technical ability. Collaboration matters a lot in CS, so colleges appreciate comments about teamwork, communication, leadership in group projects, and willingness to support others. Curiosity also stands out, especially if a teacher can say you explored concepts independently or connected classroom material to real applications.

If you have to choose between a teacher from a core STEM subject who knows you very well and a CS teacher who only knows you a little, I would usually pick the teacher who knows you better. A detailed, personal letter is almost always stronger than a vague letter from the most obvious subject.