Development and validation of immediate self-feedback very short answer questions for medical students: practical implementation of generalizability theory to estimate reliability in formative examination designs

Background Very Short Answer Questions (VSAQs) reduce cueing and simulate better real-clinical practice compared with multiple-choice questions (MCQs). While integrating them into formative exams has potential, addressing marking time and ideal occasions and items is crucial. This study gathers validity evidence of novel immediate self-feedback VSAQ (ISF-VSAQ) format and determines the optimal number of items and occasions for reliable assessment.Methods Ninety-four third-year pre-clinical students took two ten-item ISF-VSAQ exams on cardiovascular drugs. Each question comprised two sections: (1) Questions with space for student responses and (2) a list of possible correct answers offering partial-credit scores ranging from 0.00 to 1.00, along with self-marking and self-feedback options to indicate whether they fully, partially, or did not understand the possible answers. Messick's validity framework guided the collection of validity evidence.Results Validity evidence included five sources: (1) Content: The expert reviewed the ISF-VSAQ format, and the question was aligned with a standard examination blueprint. (2) Response process: Before starting, students received an example and guide to the ISF-VSAQ, and the teacher detailed the steps in the initial session to aid self-assessment. Unexpected answers were comprehensively reviewed by experts. (3) Internal structure: The Cronbach alphas are good for both occasions (>= 0.70). A generalizability study revealed Phi-coefficients of 0.60, 0.71, 0.76, and 0.79 for one to four occasions with ten items, respectively. One occasion requires twenty-five items for acceptable reliability (Phi-coefficient = 0.72). (4) Relations to other variables: Inter-rater reliability between self-marking and teacher is excellent for each item (rs(186) = 0.87-0.98,p = 0.001). (5) Consequences: Path analysis revealed that the self-reflected understanding score in the second attempt directly affected the final MCQ score (beta = 0.25,p = 0.033). However, the VSAQ score did not. Regarding perceptions, over 80% of students strongly agreed/agreed that the ISF-VSAQ format enhances problem analysis, presents realistic scenarios, develops knowledge, offers feedback, and supports electronic usability.Conclusion Electronic ISF-VSAQs enhanced understanding elevates learning outcomes, rendering them suitable for formative assessments with clinical scenarios. Increasing the number of occasions effectively enhances reliability. While self-marking is reliable and may reduce grading efforts, instructors should review answers to identify common student errors.