the conventional oral examination ( coe ) or viva voce is an important format of assessment that allows probing of breadth and depth of the knowledge . currently , this method is an integral part of formative and summative examinations in various medical universities in india . coe is criticized for being too subjective and being influenced by academic and nonacademic factors related to teachers and students . it may largely depend on the knowledge , attitude ( offering verbal / nonverbal clues and prompting ) , and mood of examiners . the process related factors are leniency , central tendency ,  halo effect ,  and error of contrast . studies have shown that scores are directly proportional to the number of words spoken by examiner and time taken by him . another pitfall of viva voce is that unequal distribution of time , that is , initially appearing students may be asked greater number of questions but as time passes , an element of fatigue ensues in examiners , and thus students giving viva in last get much less time . the outcome of this is that award of marks is based on just 23 questions asked . this is because different examiners use a different set of questions with varying difficulty levels . student related factors include gender , accent and vocabulary used , and ability to pick nonverbal cues . these factors make coe less reliable and valid assessment tool for criterion - reference system , where the intention is to ascertain achievement of predetermined level of knowledge . it is flexible , driven by student 's responses , and tests several aspects of clinical competence and ability to defend the decision in a given clinical situation that can not be tested by written examinations . it can evaluate the depth of knowledge , application and analyzing capability , ethics and professionalism . a correlation is found between viva and written components of final summative examination in pharmacology . similarly , a longitudinal study of oral practical examination within a medical program revealed internal consistency and reliability of oral examination identifying a positive correlation to in - training examination and faculty evaluation scores . to overcome the limitations of this useful tool , a few modifications are suggested such as chart - stimulated reviews , models , problem - based learning , objective structuring of clinical and practical examination , targeted viva , and structured oral examination ( soe ) . the soe is relatively a new phenomenon and a number of studies , conducted on small groups , have shown it to be reasonably reliable and valid , and both faculty and students show positive perception toward this examination tool . at present , little is known about the implementation of soe in a large group of 150250 students in a batch . because soe is a resource - intensive and time - consuming exercise , it is of utmost importance to understand the feasibility and process of implementation and factors which determine its implementation in large groups consisting of 150250 students for pharmacology examination on regular basis . the present study was designed with the primary objective to understand the process of implementation of structured viva voce examination and compare this method with the coe . other objectives were to find the suitability of soe in its present form , compare marks obtained and perceptions of students , and to obtain the feedback of faculty regarding this format . this study was conducted on the second professional students ( 140 students ) studying at a tertiary care hospital and medical college of north gujarat . the students were informed about the date of the examination 15 days prior to the examination . the marks obtained by the students in this study would not be counted in their formative or summative assessment . the students were randomly divided into four groups ( a  d ) , each of 35 students . fifteen cards each having three questions of same difficulty level were prepared by two examiners who later conducted the structured viva ( examiners b and d ) . these cards were mailed to five subject experts for comments on the language , order and relevance of the questions , entirety of topic , and any other specific comments . on the basis of comments received , the final questionnaire was prepared . the final questionnaire was pretested on 10 students and questionnaire was again modified based on the student 's feedback . on the day of examination , proper arrangement was made so that students did not interact with each other before completion of the examination . group a and c gave the unstructured ( traditional ) viva to two different examiners ( examiners a [ professor ] and examiner c [ assistant professor ] ) . similarly , groups b and d gave the structured viva to two other examiners ( examiners b and d , both associate professors ) . after the completion of the viva , each student was asked to fill a questionnaire ( four items ) to know their perception . the marks obtained by the students in different viva groups were compared using unpaired t - test , one - way anova , and post - hoc tukey test . there were 29 ( group a ) and 31 ( group c ) students who appeared in unstructured coe and 31 ( group b ) and 32 ( group d ) students appeared in soe . the mean marks obtained by coe were significantly higher than those obtained by soe [ table 1 ] . the marks allotted by examiner a ( mean = 9.43 ) were significantly lower as compared to those allotted by examiner c ( mean = 19.00 ) . similarly , marks allotted by soe showed a marked inter - examiner variability ( mean marks of examiner b vs. examiner d were 15.74 and 8.12 , respectively ) . the difficulty levels were similar for both examiners ( b and d ) , and this proves the internal consistency of the structured viva [ table 2 and figure 1 ] . comparison of marks obtained by students in soe and coe comparative frequency distribution of responders according to increasing difficulty levels of questions in soe relationship between total marks obtained by students and difficulty level of questions in structured oral examination by examiners b and d the students did not feel difficulty in responding to the structured format and over 90% students understood the questions clearly . furthermore , the students did not feel any difference in this format of viva as compared to their previous viva examinations [ table 3 ] . students feedback on soe and coe ( unstructured ) the opinion and views expressed by the teachers who conducted viva voce examination are shown in table 4 . they reported that this format led to less drift from the main topic and provided equal coverage of topics in the limited time allotted for students assessment . among the limitations , reported were difficulties in structuring viva from the entire syllabus , rigidity of time limits and knowledge content , and monotony for the teachers . most authors agree that structuring and preplanning viva voce leads to a better validity and reliability of viva as an assessment tool for under graduates and postgraduates . the results of this study show that soe format is acceptable to students and teachers and has internal consistency ( reliability ) . thus , marks awarded are objective , evidence - based as against overall ( subjective ) assessment - based award of marks in coe . there was a greater variation in mean marks allotted by two examiners in coe ( 9.419.0 ) as compared to those allotted in soe ( 9.115.7 ) . this shows that structuring the viva voce contents reduces the effect of contrasting examiner behaviors on the marks alloted ( stringent vs. lenient ) . however , structuring the contents significantly reduced the marks obtained and this is as reported elsewhere also . reduction in marks by structuring is not surprising because structuring exposes all students to all types of questions ( from easy to tough ) as against the traditional viva in which examiners preferences and chance plays role ( some students are asked too many easy questions ) . this is corroborated by the perception of teachers who have clearly stated that soe covers a wider breadth of syllabus as compared to conventional format . this could also in part be due to the fact that not all students respond to all questions having increasing difficulty levels . we found that structuring in the present form does not eliminate inter - rater variability as is reported elsewhere also . conversely , another study found perfect agreement between the marks given by two examiners in objective structured viva voce ( osvv ) while the fair agreement was found between the marks given in osvv and conventional viva . however , each student was subjected to two viva formats unlike this study on parallel groups . there can be different explanations for this discrepancy . during posttest interview of the teachers taking structured viva ( groups b and d ) , it was found that one of them used regional language frequently , while the other strictly adhered to the structured questionnaire . the examiners of the four groups had a varied teaching experience ( from 3 years to 33 years ) which determined the depth and experience in evaluating students performance . however , it is a realistic , practical situation , prevailing in most of the departments of pharmacology . training by organizing workshops and developing orientation manuals , is important for increasing effectiveness of examination . development of ability in examiners to ask relevant questions in unambiguous words so that almost similar answer comes from all students that increases validity further . inter - rater reliability can further be enhanced by the use of grading or scoring system . the perception of the students to this form of viva is found to be encouraging . in this study , students did not perceive any threat of a new format of examination and perceived structured format similar to conventional viva with respect to understanding and responding to the questions . availability of time and human resources are important determinants of the feasibility of an effective evaluation tool . at least four examiners are needed to conduct university practical examination and viva voce for 100 undergraduates and one more for every increase in 50 students . it is customary in conventional format to divide total subject into two parts according to theory paper - i and ii . one of the examiners takes viva from part - i and the other from part - ii . however , often , time becomes a big constraint [ table 5 ] . this is important because ultimately 150250 students would be required to be examined . in one study , authors fixed time duration of 1015 min for 10 items questionnaire in physiology with items having increasing difficulty levels . six examiners were involved in taking viva each assessing 67 students only . in another study , increasing number of examiners may not be a practical proposition because of professional time needed , although it reduces inter - rater variability and improves reliability ( agreement in allotted marks between two examiners ) . in a targeted viva , rangacahri engaged each student for about 25 min and thus only 56 students were examined in a day . we found that arbitrary limit of 10 min is not sufficient because students would not reach till question 14 and 15 . one remedy is to reduce the number of items in questionnaire to 10 and other is to increase the time allotted to the student . we feel that assessment of students competence for certification ( pass / fail ) would require the development of questionnaire , which includes items from various systems . therefore , reducing the number of items in the questionnaire may become counterproductive ! as shown in table 5 , increasing time duration from 10 to 15 min would result in continued work for 812 h a day ! if one examiner examines half of the students by structured viva format ( say 15 only ) and the other the remaining half , then time duration can be increased from 10 to 15 min . the entire exercise could be tiring for examiner and stressful to the examinees . at present , relationship between duration of viva , number of examiners required , and total duration required for proper conduct of soe the limitation of the present study is that it involved a single batch of students who were examined on ans only . more work is required to be done on several batches of students to ascertain a number of questions from the entire syllabus and exact time duration to successfully implement the structured viva format for final university examinations . present work suggests that structured viva voice examination is a feasible method of assessment and students feel no difficulty to this format . teachers opine that soe prevents deviations from the main topic . however , its conduct is a resource - intensive exercise and requires preplanning . there are factors , which influence the performance of students and introduce an element of inter - rater variability . these factors are the length of teaching experience , vernacular used , and lack of training of teachers . there is a need of training of examiners , development of scoring system , and ascertaining time duration of viva voce examination before soe can be implemented as a part of fulfillment of university requirement for the summative assessment of student 's performance .