One of the emergency physician's challenges is to think, to act, and to treat patients with a high level of uncertainty (for instance: incomplete past history of the patient, life-threatening decisions with poor clinical information). In recent years, Script Concordance Tests (SCTs) are increasingly used by educators to assess clinical reasoning, especially in situations of uncertainty. They compare the responses of examinees (students, trainees, or residents) with those of a panel of experts (PE). The examinee's answers are scored based on the level of agreement with responses provided by a PE. In recent years, teachers in Emergency Medicine (EM) also use SCTs. In emergency situations, the interpretation of an electrocardiogram (ECG), which is a commonly performed test, encounters a certain level of uncertainty. A last point could not be forgotten: according to the recent literature, the training of future emergency physicians remains challenging. Facing these three corner stones (uncertainty among emergency situations, uncertainty among ECG's interpretation, and challenge in training), the authors decided to construct and validate an SCT combined with an ECG (SCT-ECG) by submitting it to students, trainees, and residents during their emergency medicine clerkship rotation.