{"resourceType":"ResearchSubject","id":"example-crossover-placebo-to-drug","identifier":[{"value":"ecsr45"}],"status":"active","period":{"start":"2022-06-10"},"study":{"reference":"example-ctgov-study-record"},"subject":{"reference":"cfsb1676546565857"},"comparisonGroup":[{"concept":{"coding":[{"system":"http://hl7.org/fhir/example-comparison-group","code":"placebo","display":"Placebo"}]}},{"concept":{"text":"ap303"}}]}