This document discusses the significance of error analysis from different perspectives. It provides guidelines for designing remedial courses based on learner errors. Analyzing learner errors gives insights to teachers about their difficulties and how to address their problems. For researchers, error analysis provides evidence of how language is learned and the strategies learners use. It also shows teachers how far along learners have progressed and what they still need to learn. Error analysis can contribute to linguistic theory by discovering new aspects of language use and verifying hypotheses within linguistic frameworks.