The intention of this paper is to contribute to refining Appraisal theory, which has recently emerged from research within Systemic Functional Linguistics (SFL). Appraisal is basically concerned with a writer’s use of evaluative language. The specific aspect under investigation is the delineation of multiple coding in analysing one of the appraisal systems referred to as ATTITUDE. This paper proposes the concept of multiple coding consisting of multi-layering and double coding for the analysis of ATTITUDE. Analyses of argumentative essays written by undergraduate university students revealed that multiple coding is useful in identifying the differences between high-graded essays (HGEs) and low-graded essays (LGEs). Multi-layering and double coding of ATTITUDE occurred much more frequently in the analyses of the HGEs than LGEs.