This study aims at examining how learner L2 oral performance may vary across two different task types in the current school-based assessment initiative being implemented across secondary schools in Hong Kong. The study is innovative in that the tasks in this study involve speaking in a high-stakes language assessment context but they also build on a regular reading and viewing programme integrated into the school curriculum. An in-depth analysis of learner oral linguistic performance on two different task types, i.e., group interaction and individual presentation, from 30 ESL secondary school students, was conducted using a wide range of linguistic measures of accuracy, fluency and complexity derived from previous L2 speaking studies. The analysis shows generally systematic variation in performance dimensions across the two task types, suggesting a trend in the direction of less accuracy, lower fluency and less complex language being associated with the group discussion task. In addition, differences on rater assessments also appeared in the same direction across the two tasks as those differences on the linguistic measures. The results of this study appear to offer little support to the existing categorization of interactive tasks producing greater L2 complexity and accuracy than non-interactive tasks. Implications of the results for both test task development and classroom task design are discussed.[Copyright © Pergamon Press].