This study examined the most frequent communicative and linguistic errors made by 24 intermediate ESL students, and determined the effect of direct teacher correction upon these students' writing proficiency. Students were identified as having high or low communicative proficiency and were randomly assigned to one of two error correction treatments based on Burt and Kiparsky's global/local error distinction: correction of global errors only, or correction of global and local errors. Once a week for six consecutive weeks students wrote picture story descriptions in English and had their errors corrected according to assigned treatment. It was found that most communicative ("global") errors resulted from inadequate lexical knowledge, misuse of prepositions and pronouns, and seriously misspelled words. Most linguistic ("local") errors were caused by inappropriate lexical choice, misuse and omission of prepositions, misspelled words, lack of subject-verb agreement, and faulty word order. An analysis of variance revealed no significant differences in students' writing proficiency attributable to error correction treatment or to grouping according to communicative ability. (Author)