医学考试中减少选择题无效干扰选项方法研究

A study on reducing nonfunctional distractors of multiple-choice questions in medical examination

目的观察无效干扰选项修改后试题难度、区分度及被修改选项选择率变化,探讨通过修改无效干扰选项提高试题质量的可行性。方法以某医学基本知识考试中包含无效干扰选项的试题32题为研究对象。请专家根据命审题工作要求,在实测数据提示下,对无效干扰选项进行分析修改,观察修改前后试题的难度、区分度变化及其相关性和被修改选项选择率变化。采用SPSS 24.0进行数据处理。试题修改前后的难度、区分度及修改选项的选择率变化采用配对Wilcoxon检验;修改前和修改后试题难度、区分度相关性采用斯皮尔曼等级相关法。结果少数试题(6题)修改原因为技术性因素,多数试题(26题)修改原因为知识内容方面干扰性不强。对一个无效干扰选项进行修改后,修改前后试题难度分别为0.676(0.558,0.893)和0.637(0.531,0.839),区分度(点二列相关)分别为0.261(0.150,0.316)和0.262(0.138,0.358),区分度(鉴别指数)分别为0.215(0.113,0.352)和0.259(0.138,0.346)。修改前后难度和鉴别指数差异有统计学意义。修改前后难度和区分度均相关。被修改选项的选择率修改前为0.009(0.003,0.015),修改后为0.044(0.021,0.092),差异有统计学意义。结论本研究涉及的无效干扰选项出现的原因多数为试题内容方面,技术性缺陷相对较少。通过对无效干扰选项的分析和修改,可以有效提高无效干扰选项的选择率,提高试题难度和区分度。

Objective To discuss the possibility of modifying nonfunctional distractors to improve the quality of multiple-choice questions in medical examination through analyzing the changes in the difficulty and discrimination of items and the selection rate of modified distractors.Methods Thirty-two multiple-choice questions involving nonfunctional distractors from a medical examination were studied.According to the item-writing guidelines,experts modified nonfunctional distractors based on actual measurements.We analyzed the changes in the difficulty and discrimination of items and the selection rate of modified distractors before and after item modification using the paired Wilcoxon test,and investigated the correlation of item difficulty and discrimination before and after item modification by Spearman's rank correlation analysis.Results Six questions were modified due to technical factors,and 26 questions were modified due to weak interference in knowledge content.Before and after nonfunctional distractor modification,the difficulty values of the questions were 0.676(0.558,0.893)and 0.637(0.531,0.839),respectively;the discrimination values(point-biserial correlation)were 0.261(0.150,0.316)and 0.262(0.138,0.358),respectively;and the discrimination index values were 0.215(0.113,0.352)and 0.259(0.138,0.346),respectively.There were significant differences in the difficulty and discrimination index of items before and after modification.The difficulty and discrimination of items before and after modification were both significantly correlated.The selection rates of modified distractors were 0.009(0.003,0.015)and 0.044(0.021,0.092)before and after modification,respectively,which were significantly different.Conclusions Nonfunctional distractors in this study were mainly caused by reasons in the contents of the test questions,less in technical defects.Through the analysis and modification of nonfunctional distractors,the selection rate of nonfunctional distractors can be effectively increased,and item difficulty and discrimination can be improved.