Research On The Comparison Between Two New Indices To Detect Answer Copying

Psychological tests have much interference factors that may affect the test scores and test validity and fairness.Cheating is a relatively common factor,and in many cheating methods,answer copying is more difficult to detect.Answer copying means to answer questions by copying some or all the answers from the other respondents.In order to detect answer copying,the researchers made a lot of methods.Answer copying statistics are major methods to detect answer copying. The time using answer copying statistics to detect answer copying can be traced back to two decades in last century,then a large number of answer copying statistics were proposed.This article describes some major indices of answer copying statistics early for the detection of answer copying:K,g,ω.On this basis,this study introduce two new indices to detect answer copying in details:Kappa answer copying statistics indicator and based on the shifted binomial statistical test indicator.In this paper,the study uses Nominal Response Model for data simulation,investigating detecting rate and I-error rate of Kappa answer copying statistics and statistics based on shifted binomial statistical test in the test length,the number of items copying from others and the rate of students who copies answers and comparing the two methods.Study shows that:(1) if the number of items c copies from s reaches a certain number,detection rate of the two methods for detecting answer copying is very high. If copying rate is higher than 20%,detection rate of Kappa answer copying statistics can be as high as 0.9;if it is higher than 30%,detection rate of based on the binomial shifted statistical test of the statistical test can be as high as 0.9.(2) test length,sample size and copying rate copied have the same impact on the detection for those two methods.The longer the length of the test,the higher detection rate is.The sample size of respondents had no significant effect on detection rate.(3) Kappa statistic plagiarism detection rate of high-high-Ⅰerror rate for the price.Misjudgment rate of the theoreticalⅠ-error rate of 3～5 times.Conversion binomial statistical test-based rate control misjudgment good about in the theoretical value.