Among the variety of selected response formats used in L2 reading assessment, multiple-choice (MC) is the most commonly adopted, primarily due to its efficiency and objectiveness. Given the impact of assessment results on teaching and learning, it is necessary to investigate the degree to which the MC format reliably measures learners’ L2 reading comprehension in the classroom context. While researchers have claimed that the longer the reading test (i.e., more test items and passages), the higher its overall reliability, few studies have investigated the optimal number of items and passages required for reliable classroom-based L2 reading assessment.

To address this research gap, I adopted generalizability (G) theory to investigate the score reliability of the MC format in classroom-based L2 reading tests. A total of 108 ESL students at an American college completed an English reading test that included four passages, each of which was accompanied by five MC comprehension questions. The results showed that the score reliability of the L2 reading test was critically influenced by the number of items and passages, inasmuch as a different combination of the number of passages and items altered the degree of reliability. Implications for practitioners and educational researchers are discussed.

在 L2 阅读评估中使用的多种选定响应格式中，多项选择 (MC) 是最常用的，主要是因为它的效率和客观性。鉴于评估结果对教学和学习的影响，有必要调查 MC 格式在课堂环境中可靠地衡量学习者 L2 阅读理解的程度。虽然研究人员声称阅读测试的时间越长（即，测试项目和段落越多），其整体可靠性就越高，但很少有研究调查可靠的基于课堂的 L2 阅读评估所需的项目和段落的最佳数量。

为了弥补这一研究空白，我采用了泛化性 (G) 理论来研究 MC 格式在基于课堂的 L2 阅读测试中的分数可靠性。一所美国大学共有 108 名 ESL 学生完成了包括四篇文章的英语阅读测试，每篇文章都附有五个 MC 理解题。结果表明，二语阅读测试的分数信度受到项目和段落数量的严重影响，因为段落和项目数量的不同组合改变了信度的程度。讨论了对从业者和教育研究人员的影响。