CAS在自学考试翻译测验评分中的应用研究

计算机自动评分（CAS）用于自学考试外语类课程的翻译测验评分,能够有效提高评分效率及客观性。本研究对72名自考学习者翻译测验作答数据的计算机自动评分结果与人工评分结果进行相关分析及配对样本t检验,并将两种评分方式的诊断结果进行比较。研究发现,计算机自动评分与人工评分结果高度相关,两种评分方式的翻译测验总分无显著差异,总体而言本次翻译测验自动评分结果是可靠的;但计算机自动评分与人工评分对自考学习者的翻译能力结构诊断结果有一定差异。     

Using rasch measurement to score,evaluate, and improve examinations in an anatomy course

Any examination that involves moderate to high stakes implications for examinees should be psychometrically sound and legally defensible. Currently, there are two broad and competing families of test theories that are used to score examination data. The majority of instructors outside the high‐stakes testing arena rely on classical test theory (CTT) methods. However, advances in item response theory software have made the application of these techniques much more accessible to classroom instructors. The purpose of this research is to analyze a common medical school anatomy examination using both the traditional CTT scoring method and a Rasch measurement scoring method to determine which technique provides more robust findings, and which set of psychometric indicators will be more meaningful and useful for anatomists looking to improve the psychometric quality and functioning of their examinations. Results produced by the more robust and meaningful methodology will undergo a rigorous psychometric validation process to evaluate construct validity. Implications of these techniques and additional possibilities for advanced applications are also discussed. Anat Sci Educ 7: 450–460. © 2014 American Association of Anatomists.     

Standardization and UNDERSTANDardization in Educational Assessment

Educational tests are standardized so that all examinees are tested on the same material, under the same testing conditions, and with the same scoring protocols. This uniformity is designed to provide a level “playing field” for all examinees so that the test is “the same” for everyone. Thus, standardization is designed to promote fairness in testing. In practice, the material tested, the conditions under which a test is administered, and the scoring processes, are often too rigid to provide the intended level playing field. For example, standardized testing conditions may interact with personal characteristics of examinees that affect test performance, but are not construct-relevant. Thus, more flexibility in standardization is needed to account for the diversity of experiences, talents, and handicaps of the incredibly heterogeneous populations of examinees we currently assess. Traditional standardization procedures grew out of experimental psychology and psychophysics laboratories where keeping all conditions constant was crucial. Today, accounting for and measuring what is not constant across examinees is crucial to valid construct interpretations. To meet this need I introduce the concept of understandardization, which refers to ensuring sufficient flexibility in standardized testing conditions to yield the most accurate measurement of proficiency for each examinee.     

Effects of Differentially Time-Consuming Tests on Computer-Adaptive Test Scores

Time limits on some computer-adaptive tests (CATs) are such that many examinees have difficulty finishing, and some examinees may be administered tests with more time-consuming items than others. Results from over 100,000 examinees suggested that about half of the examinees must guess on the final six questions of the analytical section of the Graduate Record Examination if they were to finish before time expires. At the higher-ability levels, even more guessing was required because the questions administered to higher-ability examinees were typically more time consuming. Because the scoring model is not designed to cope with extended strings of guesses, substantial errors in ability estimates can be introduced when CATs have strict time limits. Furthermore, examinees who are administered tests with a disproportionate number of time-consuming items appear to get lower scores than examinees of comparable ability who are administered tests containing items that can be answered more quickly, though the issue is very complex because of the relationship of time and difficulty, and the multidimensionality of the test.     

Detection of Test Collusion via Kullback–Leibler Divergence

The development of statistical methods for detecting test collusion is a new research direction in the area of test security. Test collusion may be described as large‐scale sharing of test materials, including answers to test items. Current methods of detecting test collusion are based on statistics also used in answer‐copying detection. Therefore, in computerized adaptive testing (CAT) these methods lose power because the actual test varies across examinees. This article addresses that problem by introducing a new approach that works in two stages: in Stage 1, test centers with an unusual distribution of a person‐fit statistic are identified via Kullback–Leibler divergence; in Stage 2, examinees from identified test centers are analyzed further using the person‐fit statistic, where the critical value is computed without data from the identified test centers. The approach is extremely flexible. One can employ any existing person‐fit statistic. The approach can be applied to all major testing programs: paper‐and‐pencil testing (P&P), computer‐based testing (CBT), multiple‐stage testing (MST), and CAT. Also, the definition of test center is not limited by the geographic location (room, class, college) and can be extended to support various relations between examinees (from the same undergraduate college, from the same test‐prep center, from the same group at a social network). The suggested approach was found to be effective in CAT for detecting groups of examinees with item pre‐knowledge, meaning those with access (possibly unknown to us) to one or more subsets of items prior to the exam.     

The Contestant Perspective on Taking Tests: Emanations From the Statue Within

Views on testing—its purpose and uses and how its data are analyzed—are related to one's perspective on test takers. Test takers can be viewed as learners, examinees, or contestants. I briefly discuss the perspective of test takers as learners. I maintain that much of psychometrics views test takers as examinees. I discuss test takers as a contestant in some detail. Test takers who are contestants in high‐stakes settings want reliable outcomes obtained via acceptable scoring of tests administered under clear rules. In addition, it is essential to empirically verify interpretations attached to scores. At the very least, item and test scores should exhibit certain invariance properties. I note that the “do no harm” dictum borrowed from the field of medicine is particularly relevant to the perspective of test takers as contestants.     

A Comparison of Item Calibration Procedures in the Presence of Test Speededness

In the presence of test speededness, the parameter estimates of item response theory models can be poorly estimated due to conditional dependencies among items, particularly for end‐of‐test items (i.e., speeded items). This article conducted a systematic comparison of five‐item calibration procedures—a two‐parameter logistic (2PL) model, a one‐dimensional mixture model, a two‐step strategy (a combination of the one‐dimensional mixture and the 2PL), a two‐dimensional mixture model, and a hybrid model‐–by examining how sample size, percentage of speeded examinees, percentage of missing responses, and way of scoring missing responses (incorrect vs. omitted) affect the item parameter estimation in speeded tests. For nonspeeded items, all five procedures showed similar results in recovering item parameters. For speeded items, the one‐dimensional mixture model, the two‐step strategy, and the two‐dimensional mixture model provided largely similar results and performed better than the 2PL model and the hybrid model in calibrating slope parameters. However, those three procedures performed similarly to the hybrid model in estimating intercept parameters. As expected, the 2PL model did not appear to be as accurate as the other models in recovering item parameters, especially when there were large numbers of examinees showing speededness and a high percentage of missing responses with incorrect scoring. Real data analysis further described the similarities and differences between the five procedures.     

Evaluating an Automatically Scorable, Open-Ended Response Type for Measuring Mathematical Reasoning in Computer-Adaptive Tests

The first generation of computer-based tests depends largely on multiple-choice items and constructed-response questions that can be scored through literal matches with a key. This study evaluated scoring accuracy and item functioning for an open-ended response type where correct answers, posed as mathematical expressions, can take many different surface forms. Items were administered to 1,864 participants in field trials of a new admissions test for quantitatively oriented graduate programs. Results showed automatic scoring to approximate the accuracy of multiple-choice scanning, with all processing errors stemming from examinees improperly entering responses. In addition, the items functioned similarly in difficulty, item-total relations, and male-female performance differences to other response types being considered for the measure.     

A Statistical Test for Detecting Answer Copying on Multiple-Choice Tests

A statistical test for the detection of answer copying on multiple-choice tests is presented. The test is based on the idea that the answers of examinees to test items may be the result of three possible processes: (1) knowing, (2) guessing, and (3) copying, but that examinees who do not have access to the answers of other examinees can arrive at their answers only through the first two processes. This assumption leads to a distribution for the number of matched incorrect alternatives between the examinee suspected of copying and the examinee believed to be the source that belongs to a family of "shifted binomials." Power functions for the tests for several sets of parameter values are analyzed. An extension of the test to include matched numbers of correct alternatives would lead to improper statistical hypotheses.     

Detecting Answer Copying Using Alternate Test Forms and Seat Locations in Small-Scale Examinations

Two types of answer-copying statistics for detecting copiers in small-scale examinations are proposed. One statistic identifies the "copier-source" pair, and the other in addition suggests who is copier and who is source. Both types of statistics can be used when the examination has alternate test forms. A simulation study shows that the statistics do not depend on the total-test score. Another simulation study compares the statistics with two known statistics, and shows that they have substantial power. The new statistics are applied to data from a small-scale examination  ( N = 230)  with two alternate test forms. Auxiliary information on the seat location of the examinees and the test scores of the examinees was used to determine whether or not examinees could be suspected.     

Item Parameter Estimation Under Conditions of Test Speededness: Application of a Mixture Rasch Model With Ordinal Constraints

When tests are administered under fixed time constraints, test performances can be affected by speededness. Among other consequences, speededness can result in inaccurate parameter estimates in item response theory (IRT) models, especially for items located near the end of tests (Oshima, 1994). This article presents an IRT strategy for reducing contamination in item difficulty estimates due to speededness. Ordinal constraints are applied to a mixture Rasch model (Rost, 1990) so as to distinguish two latent classes of examinees: (a) a "speeded" class, comprised of examinees that had insufficient time to adequately answer end-of-test items, and (b) a "nonspeeded" class, comprised of examinees that had sufficient time to answer all items. The parameter estimates obtained for end-of-test items in the nonspeeded class are shown to more accurately approximate their difficulties when the items are administered at earlier locations on a different form of the test. A mixture model can also be used to estimate the class memberships of individual examinees. In this way, it can be determined whether membership in the speeded class is associated with other student characteristics. Results are reported for gender and ethnicity.     

Equating Minimum-Competency Tests: Comparisons of Methods

The 1986 scores from Florida's Statewide Student Assessment Test, Part II (SSAT-II), a minimum-competency test required for high school graduation in Florida, were placed on the scale of the 1984 scores from that test using five different equating procedures. For the highest scoring 84 % of the students, four of the five methods yielded results within 1.5 raw-score points of each other. They would be essentially equally satisfactory in this situation, in which the tests were made parallel item by item in difficulty and content and the groups of examinees were population cohorts separated by only 2 years. Also, the results from six different lengths of anchor items were compared. Anchors of 25, 20, 15, or 10 randomly selected items provided equatings as effective as 30 items using the concurrent IRT equating method, but an anchor of 5 randomly selected items did not     

Formula Scoring of Multiple-Choice Tests (Correction for Guessing)

Formula scoring is a procedure designed to reduce multiple-choice test score irregularities due to guessing. Typically, a formula score is obtained by subtracting a proportion of the number of wrong responses from the number correct. Examinees are instructed to omit items when their answers would be sheer guesses among all choices but otherwise to guess when unsure of an answer. Thus, formula scoring is not intended to discourage guessing when an examinee can rule out one or more of the options within a multiple-choice item. Examinees who, contrary to the instructions, do guess blindly among all choices are not penalized by formula scoring on the average; depending on luck, they may obtain better or worse scores than if they had refrained from this guessing. In contrast, examinees with partial information who refrain from answering tend to obtain lower formula scores than if they had guessed among the remaining choices. (Examinees with misinformation may be exceptions.) Formula scoring is viewed as inappropriate for most classroom testing but may be desirable for speeded tests and for difficult tests with low passing scores. Formula scores do not approximate scores from comparable fill-in-the-blank tests, nor can formula scoring preclude unrealistically high scores for examinees who are very lucky.     

OBTAINING MAXIMUM LIKELIHOOD TRAIT ESTIMATES FROM NUMBER-CORRECT SCORES FOR THE THREE-PARAMETER LOGISTIC MODEL

A procedure is presented for obtaining maximum likelihood trait estimates from number-correct (NC) scores for the three-parameter logistic model. The procedure produces an NC score to trait estimate conversion table, which can be used when the hand scoring of tests is desired or when item response pattern (IP) scoring is unacceptable for other (e.g., political) reasons. Simulated data are produced for four 20-item and four 40-item tests of varying difficulties. These data indicate that the NC scoring procedure produces trait estimates that are tau-equivalent to the IP trait estimates (i.e., they are expected to have the same mean for all groups of examinees), but the NC trait estimates have higher standard errors of measurement than IP trait estimates. Data for six real achievement tests verify that the NC trait estimates are quite similar to the IP trait estimates but have higher empirical standard errors than IP trait estimates, particularly for low-scoring examinees. Analyses in the estimated true score metric confirm the conclusions made in the trait metric.     

嵌入式评分标准对考生写作行为的影响

本文采用对比研究实验分析嵌入式评分标准对考生写作行为的影响,运用统计软件SPSS13．0进行独立样本t检验。研究结果表明,嵌入式评分标准能够加强考生对出题者意图的理解,写出符合写作要求的作文,但只对语言能力水平在一定阈值内的学生发生作用。这一结果丰富了Bachman和Palmer关于影响测试行为因素及途径的图式,也使出题者与考生的沟通更加具体直接,使写作考试更加人性化。     

Assessing Partial Knowledge in Vocabulary

This study reports an attempt to assess partial knowledge in vocabulary. Fifty multiple-choice vocabulary items were constructed so that the incorrect choices followed the stages of vocabulary acquisition defined by O'Connor (1940). Ability estimates based on Rasch dichotomous and polychotomous models were compared to determine if there were any gains in validity or reliability as a result of using the polychotomous scoring model rather than the dichotomous scoring model. An attempt was also made to determine the appropriateness of O'Connor's stage theory of vocabulary acquisition for predicting the type of errors that examinees of differing ability would make on the test items. The results indicate that the reliability and concurrent validity of the polychotomous scoring of a subset of items that fit the polychotomous scoring model were significantly higher than those for dichotomous scoring of the same subset of items. The results also indicate moderate support for O'Connor's theory of vocabulary acquisition.     

Two New Approaches to Assessing Differential Item Functioning: Standardization and the Mantel--Haenszel Method

The standardization and Mantel-Haenszel approaches to the assessment of differential item functioning (DIF) are described and compared. For rightwrong scoring of items, these two approaches, which emphasize the importance of comparing comparable groups of examinees, use the same data base for analysis, namely, a 2 (Group) x 2 (Item Score: Correct or Incorrect) x S (Score Level) contingency table for each item studied. The two procedures differ with respect to how they operate on these basic data tables to compare the performance of the two groups of examinees. Whereas the operations employed by Mantel-Haenszel are motivated by statistical power considerations, the operations employed by standardization are motivated by datainterpretation considerations. These differences in operation culminate in different measures of DIF effect-size that are very highly related indicators of degree of departure from the null hypothesis of no DIF.     

THE INFLUENCE OF VARIABLES OTHER THAN KNOWLEDGE ON PROBABILISTIC TESTS

In probabilistic test and scoring systems the examinee is required to respond to each of the options of a multiple-choice test with a probability which represents the confidence he has in that option. It seems reasonable to assume that for such tests to yield valid information about the examinees, the knowledge they have should be the primary influence on the probabilities they assign. The purpose of this study was to seek the relationship between the degree to which examinees display certainty in their responses and certain personality variables. Proponents of probabilistic testing would expect such correlations to be low. In this stud), it was found that individuals do respond to multiple-choice questions with a characteristic certainty that cannot be accounted for on the basis of their knowledge. This certainty was related to scores of both the F Scale and the Kogan and Wallach risk taking measure.