Source-based writing is becoming more common in tests of academic English, in part to make tests more reflective of authentic academic writing. However, the concern has been raised that over-reliance on language from the source texts in essays may mask gaps in proficiency and thus lead to an inaccurate assessment of writing skill. In this paper,…

Expert judgments of prompt difficulty in essay tests were examined to discover whether they could be used at the item-writing stage of test development. Findings show that "expert judges" share considerable agreement about prompt difficulty and prompt task type, but they cannot predict which prompts will result in high or low scores for…