Item analysis: the impact of distractor efficiency on the difficulty index and discrimination power of multiple-choice items.

BACKGROUND: Distractor efficiency (DE) of multiple-choice questions (MCQs) responses is a component of the psychometric analysis used by the examiners to evaluate the distractors' credibility and functionality. This study was conducted to evaluate the impact of the DE on the difficulty and discrimination indices. METHODS: This cross-sectional study was conducted from April to June 2023. It utilizes the final exam of the Principles of Diseases Course with 45 s-year students. The exam consisted of 60 type A MCQs. Item analysis (IA) was generated to evaluate KR20, difficulty index (DIF), discrimination index (DIS), and distractor efficiency (DE). DIF was calculated as the percentage of examinees who scored the item correctly. DIS is an item's ability to discriminate between higher and lower 27% of examinees. For DE, any distractor selected by less than 5% is considered nonfunctional, and items were classified according to the non-functional distractors. The correlation and significance of variance between DIF, DI, and DE were evaluated. RESULTS: The total number of examinees was 45. The KR-20 of the exam was 0.91. The mean (M), and standard deviation (SD) of the DIF of the exam was 37.5(19.1), and the majority (69.5%) were of acceptable difficulty. The M (SD) of the DIS was 0.46 (0.22), which is excellent. Most items were excellent in discrimination (69.5%), only two were not discriminating (13.6%), and the rest were of acceptable power (16.9%). Items with excellent and good efficiency represent 37.3% each, while only 3.4% were of poor efficiency. The correlation between DE and DIF (p = 0.000, r= -0.548) indicates that items with efficient distractors (low number of NFD) are associated with those having a low difficulty index (difficult items) and vice versa. The correlation between DE and DIS is significantly negative (P = 0.0476, r=-0.259). In such a correlation, items with efficient distractors are associated with low-discriminating items. CONCLUSIONS: There is a significant moderate negative correlation between DE and DIF (P = 0.00, r = -0.548) and a significant weak negative correlation between DE and DIS (P = 0.0476, r = -0.259). DIF has a non-significant negative correlation with DIS (P = 0.7124, r = -0.0492). DE impacts both DIF and DIS. Items with efficient distractors (low number of NFD) are associated with those having a low difficulty index (difficult items) and discriminating items. Improving the quality of DE will decrease the number of NFDs and result in items with acceptable levels of difficulty index and discrimination power.

Development of a Clinical Simulation Video to Evaluate Multiple Domains of Clinical Competence: Cross-Sectional Study.

BACKGROUND: Medical students in Japan undergo a 2-year postgraduate residency program to acquire clinical knowledge and general medical skills. The General Medicine In-Training Examination (GM-ITE) assesses postgraduate residents' clinical knowledge. A clinical simulation video (CSV) may assess learners' interpersonal abilities. OBJECTIVE: This study aimed to evaluate the relationship between GM-ITE scores and resident physicians' diagnostic skills by having them watch a CSV and to explore resident physicians' perceptions of the CSV's realism, educational value, and impact on their motivation to learn. METHODS: The participants included 56 postgraduate medical residents who took the GM-ITE between January 21 and January 28, 2021; watched the CSV; and then provided a diagnosis. The CSV and GM-ITE scores were compared, and the validity of the simulations was examined using discrimination indices, wherein ≥0.20 indicated high discriminatory power and >0.40 indicated a very good measure of the subject's qualifications. Additionally, we administered an anonymous questionnaire to ascertain participants' views on the realism and educational value of the CSV and its impact on their motivation to learn. RESULTS: Of the 56 participants, 6 (11%) provided the correct diagnosis, and all were from the second postgraduate year. All domains indicated high discriminatory power. The (anonymous) follow-up responses indicated that the CSV format was more suitable than the conventional GM-ITE for assessing clinical competence. The anonymous survey revealed that 12 (52%) participants found the CSV format more suitable than the GM-ITE for assessing clinical competence, 18 (78%) affirmed the realism of the video simulation, and 17 (74%) indicated that the experience increased their motivation to learn. CONCLUSIONS: The findings indicated that CSV modules simulating real-world clinical examinations were successful in assessing examinees' clinical competence across multiple domains. The study demonstrated that the CSV not only augmented the assessment of diagnostic skills but also positively impacted learners' motivation, suggesting a multifaceted role for simulation in medical education.

Serum lipoprotein(a) and reclassification of coronary heart disease risk; application of prediction in a cross-sectional analysis of an ongoing Iranian cohort.

INTRODUCTION: Recent studies have introduced elevated lipoprotein(a) (Lp(a)) as a risk factor for coronary heart disease (CHD). This study investigated whether the addition of Lp(a) as a novel biomarker to the Framingham Risk Score (FRS) model improves CHD risk prediction. METHODS: The study included 1101 Iranian subjects (443 non-diabetic and 658 diabetic patients) who were followed for 10 years (2003-2013). Lp(a) levels and CHD events were recorded for each participant. RESULTS: The Net Reclassification Index (NRI) after adding Lp(a) to the FRS model was 19.57% and the discrimination slope was improved (0.160 vs. 0.173). The Akaike Information Criterion (AIC), a measure of model complexity, decreased significantly after adding Lp(a) to the FRS model (691.9 vs. 685.4, P value: 0.007). CONCLUSIONS: The study concluded that adding Lp(a) to the FRS model improves CHD risk prediction in an Iranian population without making the model too complex. This could help clinicians to better identify individuals who are at risk of developing CHD and to implement appropriate preventive measures.

The Effect of a One-Day Workshop on the Quality of Framing Multiple Choice Questions in Physiology in a Medical College in India.

Background Multiple choice questions (MCQs) are commonly used in medical exams for more objectivity in assessment. However, the quality of the questions should be optimum for a proper assessment of the students. A faculty development program (FDP) may improve the quality of MCQs. The effect of a one-day workshop on framing MCQ as a part of a FDP has not been explored in our institution. Aim This study aimed to evaluate the quality of MCQ in the subject of physiology before and after a one-day workshop on framing MCQ as a part of a FDP. Methods This was a retrospective study conducted in the Department of Physiology, All India Institute of Medical Sciences, Deoghar, Jharkhand, India. A one-day workshop on framing MCQ as a part of a FDP was conducted in March 2022. We took 100 MCQs and responses from the students from examinations conducted before the workshop and 100 MCQs and responses from the students after the workshop. In pre-workshop and post-workshop, the same five faculties framed the questions. Post-validation item analysis including difficulty index (DIFI), discrimination index (DI), distractor effectiveness (DE), and Kuder-Richardson Formula 20 (KR-20) for internal consistency was calculated. Results Pre-workshop and post-workshop quality of the MCQ remain equal in terms of DIFI (chi-square {3} = 2.42, P = 0.29), DI (chi-square {3} = 2.44, P = 0.49), and DE (chi-square {3} = 4.97, P = 0.17). The KR-20 in pre-workshop and post-workshop was 0.65 and 0.87, respectively. Both had acceptable internal consistency. Conclusion The one-day workshop on framing MCQs as a part of a FDP did not have a significant impact on the quality of the MCQs as measured by the three indices of item quality but did improve the internal consistency of the MCQs. Further educational programs and research are required to find out what measures can improve the quality of MCQs.

Relations of the Number of Functioning Distractors With the Item Difficulty Index and the Item Discrimination Power in the Multiple Choice Questions.

Background Multiple choice questions (MCQ) are used nowadays in summative assessments for certification of courses, in a competitive examination, and for recruitment. A single-best-answer stem-type MCQ is one of the formats most commonly used for this purpose; it contains a question and options from which the examinee needs to select the correct answer. Item analysis is used for the determination of the quality, validity, and reliability of the MCQ. Item difficulty index, item discrimination power, and distractor effectiveness are critical for the quality of the MCQs. Aim This study was conducted to estimate the effect of distractor effectiveness on the item difficulty index and item discriminating power. Method A test paper consisting of 200 single-best-answer stem-type MCQs with four options responded to by 400 medical undergraduates was analyzed for item difficulty index, item discriminating power, and distractor effectiveness with established item analysis formulas. The effect of distractor effectiveness on item difficulty index and item discriminating power was statistically analyzed using Epi-Info 7TM software. Result The mean item difficulty index, item discriminating power, and distractor effectiveness were 57.75% ± 28.65%, 0.4388 ± 0.36, and 84.17%, respectively (p<0.05). The item difficulty index was higher for items with single-functioning distractors in comparison to items with three-functioning distractors. Item discriminating power was higher in items with three functioning distractors in comparison to items with one and two functioning distractors. Conclusion Two or three functioning distractors show an appropriate item difficulty index and item discriminating power. In addition, item discriminating power is lower for the easy MCQs. Two to three distractors are appropriate to construct a quality MCQ.

Using Data-Driven Methods and Aging Information to Quantitatively Identify Microplastic Environmental Sources and Establish a Comprehensive Discrimination Index.

The global distribution of microplastics (MPs) across various environmental compartments has garnered significant attention. However, the differences in the characteristics of MPs in different environments remain unclear, and there is still a lack of quantitative analysis of their environmental sources. In addition, the inclusion of aging in source apportionment is a novel approach that has not been widely explored. In this study, we conducted a meta-analysis of the literature from the past 10 years and extracted conventional and aging characteristic data of MPs from 321 sampling points across 7 environmental compartments worldwide. We established a data-driven analysis framework using these data sets to identify different MP communities across environmental compartments, screen key MP features, and develop an environmental source analysis model for MPs. Our results indicate significant differences in the characteristics of MP communities across environments. The key features of differentiation were identified using the LEfSe method and include the carbonyl index, hydroxyl index, fouling index, proportions of polypropylene, white, black/gray, and film/sheet. These features were screened for each environmental compartment. An environmental source identification model was established based on these features with an accuracy of 75.1%. In order to accurately represent the single/multisource case in a more probabilistic manner, we proposed the MP environmental source index (MESI) to provide a probability estimation of the sample having multiple sources. Our findings contribute to a better understanding of MP migration trends and fluxes in the plastic cycle and inform effective prevention and control strategies for MP pollution.

Right Case, Right Time: Which Procedures Best Differentiate General Surgery Trainees' Operative Performance?

OBJECTIVE: Assessing surgical trainee operative performance is time- and resource-intensive. To maximize the utility of each assessment, it is important to understand which assessment activities provide the most information about a trainee's performance. The objective of this study is to identify the procedures that best differentiate performance for each general surgery postgraduate year (PGY)-level, leading to recommendations for targeted assessment. DESIGN: The Society for Improving Medical Professional Learning (SIMPL) operative performance ratings were modeled using a multilevel Rasch model which identified the highest and lowest performing trainees for each PGY-level. For each procedure within each PGY-level, a procedural performance discrimination index was calculated by subtracting the proportion of "practice-ready" ratings of the lowest performing trainees from the proportion of "practice-ready" ratings of the highest performing trainees. Four-quadrant plots were created using the median procedure volume and median discrimination index for each PGY-level. All procedures within the upper right quadrant were considered "highly differentiating, high volume" procedures. SETTING: This study was conducted across 70 general surgical residency programs who are members of the SIMPL collaborative. PARTICIPANTS: A total of 54,790 operative performance evaluations of categorical general surgery trainees were collected between 2015 and 2021. Trainees who had at least 1 procedure in common were included. Procedures with less than 25 evaluations per training year were excluded. RESULTS: The total number of evaluations per procedure ranged from 25 to 2,131. Discrimination values were generated for 51 (PGY1), 54 (PGY2), 92 (PGY3), 105 (PGY4), and 103 (PGY5) procedures. Using the above criteria, a total of 12 (PGY1), 15 (PGY2), 22 (PGY3), 21 (PGY4), and 28 (PGY5) procedures were identified as highly differentiating, high volume procedures. CONCLUSIONS: Our study draws on national data to identify procedures which are most useful in differentiating trainee operative performance at each PGY-level. This list of procedures can be used to guide targeted assessment and improve assessment efficiency.

A comparison of the assessments used in campus-based years at the College of Medicine, Imam Abdulrahman Bin Faisal University, Saudi Arabia.

STUDY PURPOSE: Multiple assessment tools are used to assess future doctors' knowledge, clinical skills, and professional attitudes. In the present research, the difficulty level and discriminating ability of different types of written and performance-based assessments designed to measure the knowledge and competency of medical students were compared. METHODS: The assessment data of 2nd & 3rd-year medical students (the academic year 2020-2021) in the College of Medicine at Imam Abdulrahman Bin Faisal University (IAU) were retrospectively reviewed. Based on end-of-the-year overall grades, students were divided into high and low scorers. Both groups were compared by independent sample t-test for their mean scores achieved in each type of assessment. Difficulty level and discriminating ability of the assessments were also explored. MS Excel and Statistical Package for Social Sciences (SPSS version 27) were used for analysis. Area under the curve was calculated through ROC analysis. A p-value <0.05 was believed significant. RESULTS: In each type of written assessment, the high scorer group achieved significantly higher scores compared to the low scorers. Among performance-based assignments (except the PBLs), scores did not differ significantly between high and low scorers. The difficulty level of performance-based assessments was "easy" whereas it was "moderate" for written assessments (except the OSCE). The discriminating ability of performance-based assessments was "poor" whereas it was "moderate/excellent" for written assessments (except the OSCE). CONCLUSION: Our study results indicate that written assessments have excellent discriminatory ability. However, performance-based assessments are not as difficult and discriminatory as written assessments. The PBLs are relatively discriminatory among all performance-based assessments. Key messages What is already known on this topic At Imam Abdulrahman Bin Faisal University, written and performance-based assessments both are graded on criterion-referenced scales. The student's grades at the end of the year are an aggregate of his/her scores in written and performance-based assessments. What this study adds Our study results show that performance-based assessments are not as difficult and discriminatory in differentiating between high and low scorers as written assessments. How this study might affect research, practice or policy Performance-based assessments should be made a hurdle exam (pass or fail) for the students to move to the next level, or students must pass each assessment component (written and performance-based) separately.

Differentinating between non-transfusion dependant ß-thalassemia and iron deficinecy anemia in children using ROC and logistic regression analysis: two novel discrimination indices designed for pediatric patients.

Introduction: This cross-sectional study enrolled a group of 271 children with microcytic anemia in order to test the performance of 41 single and 2 composite formulas andindices in distinguishing between ß-thalassemia (ß-thal) and iron deficiency anemia (IDA) in the pediatric population. Methods: Optimal pediatric cut-off values from the previously published formulas and indices were generated using ROC analysis. Logistic regression in R using generalized linear models (GLM) generated two new indices. Results: Formulas and indices with optimal cut-offvalues in children with accuracy ≥90% were (in descending order): Matos & Carvalho index, MDHL(Telmissani) formula, England and Fraser formula, Pornprasert index, Sirachainan index, Telmissani (MCHD) formula, CRUISE index, Hameed index, Sargolzaie formula and Zaghloul II index. The CroThalDD-LM1 index has an accuracy of 93.36% (AUC 0.986, 95% CI 0.975-0.997), while the second CroThalDD-LM2 index utilizes absolute reticulocyte count alongside CBC variables, with an accuracy of 96.77% (AUC 0.985, 95% CI 0.988-0.999). Discussion and conclusion: We recommend using aforementioned formulas and indices with corrected cut-off values and accuracy >90% alongside two new proposed indices. A comparison of both native and these new indices is encouraged. These are the first discrimination indices generated and designed precisely for the pediatric population, which includes preschool children.

Amelioration of Scopolamine-Induced Cognitive Dysfunction in Experimental Mice Using the Medicinal Plant Salvia moorcroftiana.

Salvia moorcroftiana is medicinally used in various parts of the world to treat a number of diseases. In the literature, the antiamnesic activity of this plant has not yet been reported. Therefore, the current study was aimed at evaluating the in vivo antiamnesic (scopolamine-induced) potential of Salvia moorcroftiana. The major phytochemical groups such as total phenolic (TPC), total tannin (TTC), and total flavonoid content (TFC) in methanolic extract (SlMo-Crd) and subsequent fractions of Salvia moorcroftiana were quantified using standard methods. The in vitro anticholinesterase (against butyryl cholinesterase; BChE and acetylcholinesterase; AChE) and antioxidant (against 2,2-diphenyl-1-picrylhydrazyl; DPPH and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid); ABTS free radicals) potentials of crude (SIMO-Crd) extract and fractions (hexane; SlMo-Hex, chloroform; SlMo-Chl, ethyl acetate; SlMo-Et) were also determined. The SlMo-Crd at doses of 100 and 200 mg/kg body weight compared to fractions of 75 and 150 mg/kg body weight (which were 1/10th of the highest dose tested in acute toxicity tests) were evaluated for their memory enhancement and learning behavior in normal and scopolamine-induced mental dysfunction in mice using behavioral memory tests such as the Y-maze test and novel object recognition test (NORT). Moreover, the samples were further evaluated for acetylcholine contents and biochemical markers such as MDA (malondialdehyde), SOD (superoxide dismutase), CAT (catalase), and GSH (glutathione peroxidase) levels. The maximum TPC with a value of 114.81 ± 1.15 mg GAE/g, TTC with a value of 106.79 ± 1.07 mg GAE/g, and TFC with a value of 194.29 ± 0.83 mg RE/g were recorded for the SlMo-Chl fraction. Against the DPPH free radical, the methanolic extract exhibited an IC50 value of 95.29 ± 1.06 µg/mL whereas, among the fractions, the best activity was observed for the SlMo-Chl fraction with an IC50 of 75.02 ± 0.91 µg/mL, followed by SlMoS-Et with an IC50 value of 88.71 ± 0.87 µg/mL. Among the extracts, the SlMo-Chl and SlMo-Et fractions inverted the amnesic effects of scopolamine in mice effectively. Additionally, the SlMo-Chl and SIMO-Et fractions considerably enhanced the percent spontaneous alteration performance in the Y-maze test with values of 65.18 ± 2.61/69.51 ± 2.71 and 54.92 ± 2.49/60.41 ± 2.69, respectively, for the tested doses. The discrimination index (DI) in experimental mice was considerably enhanced by the SlMo-Chl in the NORT with values of 59.81 ± 1.21/61.22 ± 1.31% DI correspondingly for the tested doses, as mentioned above, followed by the SlMo-Et extract. The selected plant in the form of extracts ameliorated the effects of amnesia in mice and could, therefore, be used as a therapy for amnesia; however, this is subject to further exploration in other animal models and the isolation of the responsible compounds.

A Novel Risk Score to Predict In-Hospital Mortality in Patients With Acute Myocardial Infarction: Results From a Prospective Observational Cohort.

Objectives: The aim of this study was to develop and validate a novel risk score to predict in-hospital mortality in patients with acute myocardial infarction (AMI) using the Heart Failure after Acute Myocardial Infarction with Optimal Treatment (HAMIOT) cohort in China. Methods: The HAMIOT cohort was a multicenter, prospective, observational cohort of consecutive patients with AMI in China. All participants were enrolled between December 2017 and December 2019. The cohort was randomly assigned (at a proportion of 7:3) to the training and validation cohorts. Logistic regression model was used to develop and validate a predictive model of in-hospital mortality. The performance of discrimination and calibration was evaluated using the Harrell's c-statistic and the Hosmer-Lemeshow goodness-of-fit test, respectively. The new simplified risk score was validated in an external cohort that included independent patients with AMI between October 2019 and March 2021. Results: A total of 12,179 patients with AMI participated in the HAMIOT cohort, and 136 patients were excluded. In-hospital mortality was 166 (1.38%). Ten predictors were found to be independently associated with in-hospital mortality: age, sex, history of percutaneous coronary intervention (PCI), history of stroke, presentation with ST-segment elevation, heart rate, systolic blood pressure, initial serum creatinine level, initial N-terminal pro-B-type natriuretic peptide level, and PCI treatment. The c-statistic of the novel simplified HAMIOT risk score was 0.88, with good calibration (Hosmer-Lemeshow test: P = 0.35). Compared with the Global Registry of Acute Coronary Events risk score, the HAMIOT score had better discrimination ability in the training (0.88 vs. 0.81) and validation (0.82 vs. 0.72) cohorts. The total simplified HAMIOT risk score ranged from 0 to 121. The observed mortality in the HAMIOT cohort increased across different risk groups, with 0.35% in the low risk group (score ≤ 50), 3.09% in the intermediate risk group (50 < score ≤ 74), and 14.29% in the high risk group (score > 74). Conclusion: The novel HAMIOT risk score could predict in-hospital mortality and be a valid tool for prospective risk stratification of patients with AMI. Clinical Trial Registration: [https://clinicaltrials.gov], Identifier: [NCT03297164].

Effects of Artemisia macrocephala Jacquem on Memory Deficits and Brain Oxidative Stress in Streptozotocin-Induced Diabetic Mice.

Different species of Artemisia have been reported to have therapeutic potential in treating various health disorders, including diabetes and memory dysfunction. The present study was planned to evaluate the effects of Artemisia macrocephala Jacquem crude extract and its subfractions as antiamnesic agents in streptozotocin-induced (STZ) diabetic mice. The in vivo behavioral studies were performed using the Y Maze test and novel object recognition test (NORT) test at doses of 100 and 200 mg/kg of crude extract and 75 and 150 mg/kg of fractions. The in vitro and ex vivo anticholinesterase activities, along with biochemical parameters (superoxide dismutase, catalase, glutathione and lipid peroxidation) in the brain, were evaluated. Blood glucose levels were monitored with a glucometer; crude extract and fractions reduced the glucose level considerably, with some differences in the extent of their efficacies. The crude extract and fractions demonstrated significant inhibitory activity against cholinesterases (AChE and BuChE) in vitro. Crude, chloroform and ethyl acetate extract were found to be more potent than the other fractions, with IC50 of Crd-Am = 116.36 ± 1.48 and 240.52 ± 1.35 µg/mL, Chl-Am = 52.68 ± 1.09 and 57.45 ± 1.39 µg/mL and Et-Am = 75.19 ± 1.02 and 116.58 ± 1.09 µg/mL, respectively. Oxidative stress biomarkers like superoxide dismutase, catalase and glutathione levels were elevated, whereas MDA levels were reduced by crude extract and all fractions with little difference in their respective values. The Y-maze test and novel object recognition test demonstrated declines in memory impairment in groups (n = 6) treated with crude extract and fractions as compared to STZ diabetic (amnesic) group. The most active fraction, Chl-Am, was also subjected to isolation of bioactive compounds; three compounds were obtained in pure state and designated as AB-I, AB-II and AB-III. Overall, the results of the study showed that Artemisia macrocephala Jacquem enhanced the memory impairment associated with diabetes, elevated acetylcholine levels and ameliorated oxidative stress. Further studies are needed to explore the beneficial role of the secondary metabolites isolated in the present study as memory enhancers. Toxicological aspects of the extracts are also important and need to be evaluated in other animal models.

Evaluation of Multiple-Choice Questions by Item Analysis, from an Online Internal Assessment of 6th Semester Medical Students in a Rural Medical College, West Bengal.

Background: Properly constructed single best-answer multiple choice questions (MCQs) or items assess higher-order cognitive processing of Bloom's taxonomy and accurately discriminate between high and low achievers. However, guidelines for writing good test items are rarely followed, leading to generation and application of faulty MCQs. Materials and Methods: During lockdown period in 2020, internal assessment was taken through online mode using Google Forms. There were 60 'single response type' MCQs, each consisting of single stem and four options including one correct answer and three distractors. Each item was analyzed for difficulty index (Dif I), discrimination index (DI), and distractor efficiency (DE). Results: The mean of achieved marks was 42.92± (standard deviation [SD], 5.07). Dif I, DI, and DE were 47.95± (SD 16.39) in percentage, 0.12± (SD 0.10), and 18.42± (SD 15.35), respectively. 46.67% of the items were easy and 21.66% were of acceptable discrimination. Very weak negative correlation was found between Dif I and DI. Out of total 180 distractors, 51.66% were nonfunctional one. Conclusion: Item analysis and storage of MCQs with their indices provides opportunity for an examiner to select MCQs of appropriate difficulty level as per the need of assessment and decide their placement in the question paper.

Differentiating Cardiac and Pulmonary Causes of Dyspnea Using Ultrasonography and Dyspnea Discrimination Index.

BACKGROUND: One of the most common reasons for emergency room (ER) visits is acute dyspnea. The challenge is in differentiating a cardiac and pulmonary cause of acute breathlessness. Hence, we have studied the effectiveness of the dyspnea discrimination index (DDI) used in conjunction with ultrasonography (USG) in distinguishing between cardiac and pulmonary causes of dyspnea. METHODS: This was a prospective study conducted in the ER and general medicine wards to evaluate the efficacy of the DDI and USG in dyspneic patients. Data were entered in a standard data sheet and analysis was done using SPSS software. RESULTS: The majority of the patients were between the ages of 45 and 60, with a male predominance. Risk factors like smoking were more common in the pulmonary group (36%). Pulmonary cause of breathlessness was seen in 62% of patients and cardiac pathology was noted in 28%. The mean (SD) DDI value and DDI% are as follows: pulmonary group (DDI)-5.47 (SD: 2.82); cardiac group (DDI)-8.34 (SD: 3.75); pulmonary group (DDI%)-1.31 (SD: 0.68); cardiac group (DDI%)-2.34 (SD: 1.14). There was a significant difference in DDI% between the pulmonary and cardiac groups (p = 0.001). DDI was found to have a sensitivity and specificity of 77.3% and 70%, respectively. While for DDI%, sensitivity and specificity were 72.7% and 72%, respectively. Lung USG had 98% sensitivity and 95.5% specificity, with a narrow confidence interval. The positive likelihood ratio was noted to be 21.6, indicating a very high post-test probability. CONCLUSION: The DDI and USG in conjunction had good discriminative power, when it came to distinguishing between cardiac and pulmonary causes of dyspnea. USG had a high specificity and sensitivity, making it suitable for identifying the cause of dyspnea in a tertiary care ER setting. HOW TO CITE THIS ARTICLE: Chandy GM, Sathyendra S, Pichamuthu K, Hazra D, Abhilash KPP. Differentiating Cardiac and Pulmonary Causes of Dyspnea Using Ultrasonography and Dyspnea Discrimination Index. Indian J Crit Care Med 2022;26(1):33-38.

Item Analysis of the Modified Version of the Routine Blood Transfusion Knowledge Questionnaire.

Background and Purpose: Item analysis is important in examining the quality of items. The main aims of this sub-study were to assess and improve the psychometric properties of the modified version of the Routine Blood Transfusion Knowledge Questionnaire (RBTKQ-2) and produce an optimized version (RBTKQ-O) of it. Methods: Statistical item analysis was performed on the RBTKQ-2 after completion by 305 nurses. Results: There were one (3%) easy, 15 (47%) moderately difficult, and 16 (50%) difficult items. Twenty six (81%) items and six (19%) had positive significant and weak point-biserial correlation respectively. The majority of distractors (n = 66, 64%) were functional. Four sources of information, including item analysis data, informed the development of the RBTKQ-O. Conclusions: The RBTKQ-O addressed the limitations that were identified in the versions published earlier. This version can be used by researchers and academics worldwide.

Evaluation of competing risks prediction models using polytomous discrimination index.

For competing risks data, it is often important to predict a patient's outcome status at a clinically meaningful time point after incorporating the informative censoring due to competing risks. This can be done by adopting a regression model that relates the cumulative incidence probabilities to a set of covariates. To assess the performance of the resulting prediction tool, we propose an estimator of the polytomous discrimination index applicable to competing risks data, which can quantify a prognostic model's ability to discriminate among subjects from different outcome groups. The proposed estimator allows the prediction model to be subject to model misspecification and enjoys desirable asymptotic properties. We also develop an efficient computation algorithm that features a computational complexity of O(n log n). A perturbation resampling scheme is developed to achieve consistent variance estimation. Numerical results suggest that the estimator performs well under realistic sample sizes. We apply the proposed methods to a study of monoclonal gammopathy of undetermined significance.

Lorsque des données comportent des risques concurrents, il est souvent important de prédire l'issue pour un patient à un temps significatif d'un point de vue clinique après avoir incorporé la censure informative due aux risques concurrents, ce qui peut être fait en adaptant un modèle de régression qui lie les probabilités cumulatives d'incidence à un ensemble de covariables. Pour évaluer la performance des outils de prévision qui en découlent, les auteurs proposent un estimateur de l'indice de discrimination polytomique applicable aux données avec des risques concurrents, et qui permet de quantifier l'habileté d'un modèle de pronostic à discriminer entre les sujets de différents groupes de dénouement. L'estimateur proposé permet au modèle de prévision un certain nombre de mauvaises classifications et exhibe des propriétés asymptotiques souhaitables. Les auteurs développent un algorithme efficace dont la complexité de calcul est d'ordre O(n log n). Ils proposent un schéma de rééchantillonnage pour obtenir une estimation convergente de la variance et présentent des résultats numériques qui suggèrent que leur estimateur offre de bonnes performances avec des tailles d'échantillons réalistes. Ils appliquent finalement leur méthode à une étude de gammopathie monoclonale dont la significativité n'est pas établie.

The role of contingency discriminability in suboptimal choice.

Suboptimal choice consists of a preference for an alternative with a lower probability of reinforcement (suboptimal alternative) over another with a higher probability of reinforcement (optimal alternative) when the former has discriminative stimuli that signal in which trials a reinforcer will be delivered and in which trials it will not. Discriminating the contingencies of reinforcement associated with the stimuli of the suboptimal alternative is necessary to produce suboptimal choice, but the impact of different degrees of discriminability has not been systematically studied. The discriminability of the contingencies of reinforcement depends on the difference in the probability of reinforcement of the two stimuli; higher differences yield higher discriminability. Pigeons were exposed to a procedure that presented a choice between two alternatives, each associated with two stimuli. The contingency discriminability of the suboptimal alternative was manipulated across conditions, while the contingency discriminability of the optimal alternative was absent in all conditions. The overall probability of reinforcement of each alternative remained the same throughout the experiment (p = .2 and p = .5 for the suboptimal and optimal alternatives, respectively). The preference for the suboptimal alternative increased as its discriminability increased. There was a positive correlation between discrimination index and preference for the suboptimal alternative. These results highlight the importance of contingency discriminability to generate suboptimal choice.

New Item Selection Method Accommodating Practical Constraints in Cognitive Diagnostic Computerized Adaptive Testing: Maximum Deviation and Maximum Limitation Global Discrimination Indexes.

Maximum deviation global discrimination index (MDGDI) is a new item selection method for cognitive diagnostic computerized adaptive testing that allows for attribute coverage balance. We developed the maximum limitation global discrimination index (MLGDI) from MDGDI, which allows for both attribute coverage balance and item exposure control. MLGDI can realize the attribute coverage balance and exposure control of the item. Our simulation study aimed to evaluate the performance of our new method against maximum global discrimination index (GDI), modified maximum GDI (MMGDI), standardized weighted deviation GDI (SWDGDI), and constraint progressive with SWDGDI (CP_SWDGDI). The results indicated that (1a) under the condition of realizing the attribute coverage balance, MDGDI had the highest attribute classification accuracy; (1b) when the selection strategy accommodated the practical constraints of the attribute coverage balance and item exposure control, MLGDI had the highest attribute classification accuracy; (2) adding the item exposure control mechanism to the item selection method reduces the classification accuracy of the attributes of the item selection method; and (3) compared with GDI, MMGDI, SWDGDI, CP_SWDGDI, and MDGDI, MLGDI can better achieve the attribute-coverage requirement, control item exposure rate, and attribute correct classification rate.

Computing the polytomous discrimination index.

Polytomous regression models generalize logistic models for the case of a categorical outcome variable with more than two distinct categories. These models are currently used in clinical research, and it is essential to measure their abilities to distinguish between the categories of the outcome. In 2012, van Calster et al proposed the polytomous discrimination index (PDI) as an extension of the binary discrimination c-statistic to unordered polytomous regression. The PDI is a summary of the simultaneous discrimination between all outcome categories. Previous implementations of the PDI are not capable of running on "big data." This article shows that the PDI formula can be manipulated to depend only on the distributions of the predicted probabilities evaluated for each outcome category and within each observed level of the outcome, which substantially improves the computation time. We present a SAS macro and R function that can rapidly evaluate the PDI and its components. The routines are evaluated on several simulated datasets after varying the number of categories of the outcome and size of the data and two real-world large administrative health datasets. We compare PDI with two other discrimination indices: M-index and hypervolume under the manifold (HUM) on simulated examples. We describe situations where the PDI and HUM, indices based on multiple comparisons, are superior to the M-index, an index based on pairwise comparisons, to detect predictions that are no different than random selection or erroneous due to incorrect ranking.

Item analysis of multiple choice questions: A quality assurance test for an assessment tool.

BACKGROUND: The item analysis of multiple choice questions (MCQs) is an essential tool that can provide input on validity and reliability of items. It helps to identify items which can be revised or discarded, thus building a quality MCQ bank. METHODS: The study focussed on item analysis of 90 MCQs of three tests conducted for 150 first year Bachelor of Medicine and Bachelor of Surgery (MBBS) physiology students. The item analysis explored the difficulty index (DIF I) and discrimination index (DI) with distractor effectiveness (DE). Statistical analysis was performed by using MS Excel 2010 and SPSS, version 20.0. RESULTS: Of total 90 MCQs, the majority, that is, 74 (82%) MCQs had a good/acceptable level of difficulty with a mean DIF I of 55.32 ± 7.4 (mean ± SD), whereas seven (8%) were too difficult and nine (10%) were too easy. A total of 72 (80%) items had an excellent to acceptable DI and 18 (20%) had a poor DI with an overall mean DI of 0.31 ± 0.12. There was significant weak correlation between DIF I and DI (r = 0.140, p < .0001). The mean DE was 32.35 ± 31.3 with 73% functional distractors in all. The reliability measure of test items by Cronbach alpha was 0.85 and Kuder-Richardson Formula 20 was 0.71, which is good. The standard error of measurement was 1.22. CONCLUSION: Our study helped teachers identify good and ideal MCQs which can be part of the question bank for future and those MCQs which needed revision. We recommend that item analysis must be performed for all MCQ-based assessments to determine validity and reliability of the assessment.