<status value="active"/> <author> <name value="Brian S. Alper, MD, MSPH"/> </author> <publisher value="HL7 International / Clinical Decision Support"/> <contact> <telecom> <system value="url"/> <value value="http://www.hl7.org/Special/committees/dss"/> </telecom> </contact> <copyright value="https://creativecommons.org/licenses/by-nc-sa/4.0/"/> <description value="This example uses the StatisticModelIncludeIf extension to represent the model characteristic of Welch's 2-sample t-test if the data is consistent with a normal distribution (based on Shapiro-Wilk test with p-value >= 0.05) and a Wilcoxon Mann-Whitney test if not."/> <variableDefinition> <description value="Adults with hypertension"/> <variableRole value="population"/> </variableDefinition> <variableDefinition> <description value="Reversitol vs. Placebo"/> <variableRole value="exposure"/> </variableDefinition> <variableDefinition> <description value="Change in systolic blood pressure from baseline to 3 months"/> <variableRole value="outcome"/> </variableDefinition> <studyDesign> <coding> <system value="https://fevir.net/sevco"/> <code value="SEVCO:01003"/> <display value="randomized assignment"/> </coding> </studyDesign> <statistic> <statisticType> <coding> <system value="https://fevir.net/sevco"/> <code value="STATO:0000457"/> <display value="difference in means"/> </coding> </statisticType> <modelCharacteristic> <extension url="http://hl7.org/fhir/StructureDefinition/statistic-model-include-if"> <extension url="attribute"> <valueCodeableConcept> <text value="data distribution"/> </valueCodeableConcept> </extension> <extension url="value"> <valueCodeableConcept> <text value="normal distribution (Shapiro-Wilk test with p-value >= 0.05)"/> </valueCodeableConcept> </extension> </extension> <code> <text value="Welch's 2-sample t-test"/> </code> <intended value="true"/> </modelCharacteristic> <modelCharacteristic> <extension url="http://hl7.org/fhir/StructureDefinition/statistic-model-include-if"> <extension url="attribute"> <valueCodeableConcept> <text value="data distribution"/> </valueCodeableConcept> </extension> <extension url="value"> <valueCodeableConcept> <text value="not consistent with normal distribution (Shapiro-Wilk test with p-value < 0.05)"/> </valueCodeableConcept> </extension> </extension> <code> <text value="Wilcoxon Mann-Whitney test"/> </code> <intended value="true"/> </modelCharacteristic> </statistic> </Evidence>