A 2-year project investigated the ability of secondary school teachers to identify the top 10 percent of students in each of four subjects, English, French, physics, and mathematics. The students were tested on a wide range of aptitudes and attitudes at the beginning of their third form (ninth grade). Teachers were asked to list students they considered high or outstanding in potential in their subject. Encouraging levels of agreement were found in all four subjects, though there was some evidence of errors in physics and French. Test-identifiable characteristics of the teacher-selected students were examined to discover clues to possible biases affecting teacher judgment. Physics teachers tended to place emphasis on general ability rather than subject-specific abilities, while French teachers tended to select students with favorable attitudes toward the subject. Subsequently, the school sample was divided into two groups. One group of teachers made ability selections in the same way as before, while the other filled in a subject-specific profile of aptitudes using checklists as an aid to identification. The conclusion was reached that the checklists had little effect on the ability of teachers to identify able students. (JD)