comparison study between the conventional mcq scores & mcq with cba scores at the standardized clinical knowledge exam in clinical medical students.

abstract:             partial knowledge is one of the main factors to take into account when dealing with the improvement of administration of multiple choice questions (mcq). various strategies have been proposed for this factor in traditional testing environment. so this study proposed a confidence based assessment (cba) as a sufficient solution & want to compare the effect of cba scoring system with the conventional scoring systems (with & without negative score estimation as penalty) on the students scores & estimation of thire partial knowledge on clinical knowledge.             this comparative study perform by a standardized clinical knowledge exam among 117 clinical students. after 2-step training, both of conventional mcq and cba exam is given in one session simultaneously. the exam has 100 questions & asked the volunteers to complete the questioner about their attitude and satisfaction in first experience on cba after exam. a new confidence based marking system is chosen for scoring, that is a hybrid of ucl & muk2010 systems. mcq-assistant, spss & microsoft office excel softwares  were used for scoring & analysis of the data.             mean age of volunteers was 27.3±5.47, 43.6% of them were men & 69.2% were senior medical student. exam reliability was 0.977. fit line of mcq scores without penalty estimation has a r 2 =0.9816, intercept=18.125 or approximately 0.2 deviation in low scores. mcq scoring with penalty has a fit line approximately parallel to the 45-degree line but on above it & cba scoring fit line is a nearer to the 45-degree line, parallel to it and a little below it. these two set of scores has a significant p-value=0.037. response percentage to cba is higher (p-value: 0.0001). discrimination power of mcq & cba for upper & lower 1/3 of the students was not significantly different (p-value: 0.34). students satisfaction was high and acceptable for cba system and students have a positive viewpoint to this system for their examinations.             cba method can increase the competencies of the mcq exams & it has a more fairness assessment, effective exam, authentic test, precise estimation & higher construct validity than conventional mcq exam. cba simulate the reflection for deeper learning among the students.