<status value="draft"/><publisher value="HL7 International / Clinical Decision Support"/><contact><telecom><system value="url"/><value value="http://www.hl7.org/Special/committees/dss"/></telecom></contact><description value="Placebo"/><actual value="true"/><definition><concept><coding><system value="http://snomed.info/sct"/><code value="182886004"/><display value="Placebo given (situation)"/></coding></concept></definition><handling/></EvidenceVariable>

In a study of response rates if placebo is given, "placcebo given" may be the variable for the exposure of interest.