Assessment of Reasoning Tool (ART)

Purpose

• To assess a learner's ability to construct a prioritized differential diagnosis.
• Focus on probability ranking based on problem representation.

Steps in Constructing a Prioritized Differential Diagnosis

1. Select Leading Hypothesis
   • Choose the most probable diagnosis based on available evidence.
2. Consider Can't-Miss Hypotheses
   • Identify serious or emergent diseases that must not be overlooked.
3. Consider Less Likely and Unlikely Hypotheses
   • Evaluate alternative diagnoses that are less probable.

Problem Representation

• A concise synthesis of the clinical problem.
• Addresses three key questions:
  • Who is the patient?
  • What is the clinical syndrome?
  • What is the time course?
• Compare potential diseases (illness scripts) with the problem representation.
• Higher match increases the likelihood of a diagnosis explaining the patient's presentation.

Evidence in Diagnosis Ranking

• Accompany diagnoses with clinical evidence that supports or refutes each possibility.
• Include consideration for can't-miss diagnoses.

Evaluating Learner's Reasoning

• Analyze spoken or written assessments for main problems.

Case Study Example

High Performer Example

• Patient: Julio Martinez, 27-year-old woman, hyperthyroidism, two days of nausea, vomiting, diarrhea, left upper quadrant pain.
• Most Likely: Viral gastroenteritis (nausea, vomiting, diarrhea, acuity).
• Less Likely: Food poisoning (absence of illness in dining companions).
• Unlikely: Appendicitis (location and diarrhea don't match).
• Can't-Miss: Ectopic pregnancy (considered in young women with abdominal pain).
• Note: Clear probability tiers and evidence for/against each condition.

Low Performer Example

• Lists diagnoses: appendicitis, ectopic pregnancy, food poisoning.
• Acknowledges emergent conditions but lacks probability delineation.
• No evidence for or against diagnoses.

Summary

• A prioritized differential diagnosis ranks diseases based on their match to the problem representation.
• Must include can't-miss diagnoses.
• Should articulate supporting and refuting evidence for each diagnosis.