Diverse strategies for marking GCSE examinations have been identified, ranging from simple automatic judgements to complex cognitive operations requiring considerable expertise. However, little is known about patterns of strategy usage or how such information could be utilised by examiners. We conducted a quantitative analysis of previous verbal protocol data collected from twelve experienced examiners using a concurrent "think aloud" method. Two contrasting examination papers had been marked: mathematics and business studies. Five senior examiners were interviewed about the findings. The analysis revealed differences in strategy usage among individual examiners, but most strikingly, between subjects and among question parts. For most questions, examiners used strategy combinations rather than single strategies. Business studies question parts could be categorised according to whether they entailed simple or complex strategies. However, most mathematics question parts entailed a mixture of diverse strategies. The examiners identified potential implications of the findings for examiner training and modernising marking systems. (Contains 1 table, 4 figures and 5 notes.)