The widespread application of SPs in medical education reflects the improvement in humanistic quality and care in society. Through trained SPs, students who are going to work are taught how to communicate with patients and deal with unexpected problems, experience humanistic care for patients, and improve their abilities to identify, analyze, and deal with problems. The clinical thinking abilities of medical students can be improved by SP inquiry and physical examinations, communicating with SPs, understanding patients' experience of illness, and providing health education to patients [12]. Through personal experience combined with the actual situation and scoring rubrics, SPs assess students, record and identify their shortcomings, and provide students with a realistic and comprehensive clinical process and real feelings. Applying SPs under the framework of OSCE makes the assessment more fair and just. Each SP is trained for one aspect, so that each SP faces the same patients and the same problems, making the evaluation fair and true and thus avoiding previous biases caused by collecting medical histories and signs of different patients by different students.
OSCE is designed to standardize the examination and reduce variables that may affect performance assessment. Thus, for a well-designed OSCE, the examination results of examinees are mainly affected by their own competencies, ensuring minimal interference from other variances. The consistency of SP performance for each examinee is crucial for the SP station. Poorly standardized SPs perform differently for different examinees, reducing the reliability of examination [13]. Therefore, the training of examiners and SPs is an important element in the quality assurance and standardization process before the examination [14]. In the present study, SPs were trained three times before the examination, and SPs and matched examiners were trained two times. The training not only included the explanation of scripts and scoring rubrics but also analyzed previous examination videos and organized the training of simulated examinees. A checklist with detailed contents was designed, listing the assessment points of examinees in communication, to increase the consistency of the assessment. Through careful pre-exam design and training, regardless of examiners, these measures can reduce the differences in examiners and improve behavioral consistency, thereby increasing the reliability of the examination [15]. The results showed no significant difference in the annual scores between SPs and examiners. In the four years from 2018 to 2021, a significant positive correlation was found between SPs and examiners in the scores of 10 items at this station, suggesting good reliability and higher consistency of assessors. However, some studies demonstrated statistical differences in the scores given by different types of examiners to the same examinees; this result might be associated with their insufficient preparation for the examination [16].
The selection of SP as the station examiner can reduce large numbers of examiners at OSCE. More importantly, real feedback can be obtained from patients. A previous study has also shown that medical students believe that the most valuable part of SP training and assessment is the direct feedback from patients, “This is a very rare opportunity because we rarely obtain this feedback from real patients and their families” [17]. During the assessment, it was also found that the SP was more likely to propose some details that might be neglected by the examiners, such as “he (she) doesn’t look at me during the communication,” “my speech is interrupted,” “he (she) is unable to empathize with my pain,” “the movement during the examination is rude,” “the explanation of the conditions is too professional,” and so forth. As professionals, examiners may be familiar with disease settings and think that comfort and explanation are unnecessary. At the same time, as a bystander, examiners cannot share the experience of the patients gained by the manipulation of the examinees. Thus, a qualified SP understands case contents well and can provide positive, helpful feedback on the performance of examinees.
The type of patients required for a SP station depends on assessment contents and the role they are expected to play. The assessment contents in the present station require examinees to perform an oral examination based on the chief complaints, provide possible diagnosis and treatment plans based on the examination results, and communicate with patients. Given oral diseases are often obvious, for humanitarian reasons, the oral disease status of the SP cannot be maintained without treatment for a long time. Therefore, SPs are selected and trained before the assessment, and they cannot perform long-term tasks. Moreover, the replacement frequency is high. Thus, experienced training teachers and a whole set of standardized selection and training processes are required to ensure the consistency of the examination. Other limitations of the present study include small sample size of students and examiners and a shorter observation time so that the conclusions are not generalized. More SPs will be used as assessors and instructors in the education of medical students in the future.