diff --git a/pom.xml b/pom.xml
index 6b2166f..055e6e5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,7 +5,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>gov.cms.madie</groupId>
 	<artifactId>madie-translator-commons</artifactId>
-	<version>2.0.2-SNAPSHOT</version>
+	<version>2.0.3-SNAPSHOT</version>
 	<properties>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<java.version>17</java.version>
diff --git a/src/main/java/gov/cms/madie/cql_elm_translator/utils/cql/CQLTools.java b/src/main/java/gov/cms/madie/cql_elm_translator/utils/cql/CQLTools.java
index 8da0f57..f7f956d 100644
--- a/src/main/java/gov/cms/madie/cql_elm_translator/utils/cql/CQLTools.java
+++ b/src/main/java/gov/cms/madie/cql_elm_translator/utils/cql/CQLTools.java
@@ -398,12 +398,13 @@ private void collectReturnTypeMap() {
     this.allNamesToReturnTypeMap.put(libraryName + "-" + libraryVersion, new HashMap<>());
 
     for (ExpressionDef expression : statements.getDef()) {
+      String resultType =
+          expression.getResultType() == null ? null : expression.getResultType().toString();
       this.allNamesToReturnTypeMap
           .get(libraryName + "-" + libraryVersion)
-          .put(expression.getName(), expression.getResultType().toString());
-      this.nameToReturnTypeMap.put(expression.getName(), expression.getResultType().toString());
-      this.expressionToReturnTypeMap.put(
-          expression.getName(), expression.getResultType().toString());
+          .put(expression.getName(), resultType);
+      this.nameToReturnTypeMap.put(expression.getName(), resultType);
+      this.expressionToReturnTypeMap.put(expression.getName(), resultType);
     }
 
     if (parameters != null) {
diff --git a/src/test/java/gov/cms/madie/cql_elm_translator/utils/cql/CQLToolsTest.java b/src/test/java/gov/cms/madie/cql_elm_translator/utils/cql/CQLToolsTest.java
index b337490..e93d9d0 100644
--- a/src/test/java/gov/cms/madie/cql_elm_translator/utils/cql/CQLToolsTest.java
+++ b/src/test/java/gov/cms/madie/cql_elm_translator/utils/cql/CQLToolsTest.java
@@ -1,18 +1,29 @@
 package gov.cms.madie.cql_elm_translator.utils.cql;
 
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.hamcrest.CoreMatchers.nullValue;
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.jupiter.api.Assertions.*;
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
+import lombok.extern.slf4j.Slf4j;
 import org.cqframework.cql.cql2elm.CqlTranslator;
 import org.cqframework.cql.cql2elm.model.CompiledLibrary;
 import org.cqframework.cql.cql2elm.model.ResolvedIdentifierContext;
+import org.hl7.cql.model.DataType;
+import org.hl7.elm.r1.IncludeDef;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
@@ -26,6 +37,7 @@
 import org.hl7.elm.r1.ExpressionDef;
 
 @ExtendWith(MockitoExtension.class)
+@Slf4j
 class CQLToolsTest {
 
   @Mock private CqlTranslator cqlTranslator;
@@ -33,6 +45,8 @@ class CQLToolsTest {
   @Mock private Library library;
   @Mock private ResolvedIdentifierContext element;
   @Mock private Statements statements;
+  @Mock private Library.Includes includes;
+  @Mock private Map<String, CompiledLibrary> compiledLibraryMap;
 
   VersionedIdentifier versionedIdentifier = new VersionedIdentifier();
 
@@ -59,4 +73,66 @@ void testGenerate() {
       fail();
     }
   }
+
+  @Test
+  void testItHandlesNullExpressionResultType() {
+    versionedIdentifier.setId("local");
+    String cqlData = ResourceUtils.getData("/tooling_test_qicore6.cql");
+    doReturn(statements).when(library).getStatements();
+    doReturn(compiledLibrary).when(cqlTranslator).getTranslatedLibrary();
+    doReturn(library).when(compiledLibrary).getLibrary();
+    doReturn(versionedIdentifier).when(compiledLibrary).getIdentifier();
+    doReturn(element).when(compiledLibrary).resolve(any(String.class));
+    doReturn(includes).when(library).getIncludes();
+
+    ExpressionDef expression1 = mock(ExpressionDef.class);
+    DataType booleanDataType = mock(DataType.class);
+    doReturn(booleanDataType).when(expression1).getResultType();
+    doReturn("expression1").when(expression1).getName();
+    doReturn("System.Boolean").when(booleanDataType).toString();
+
+    ExpressionDef expression2 = mock(ExpressionDef.class);
+    doReturn("expression2").when(expression2).getName();
+    doReturn(null).when(expression2).getResultType();
+
+    List<ExpressionDef> expressionDefs = List.of(expression1, expression2);
+
+    doReturn(expressionDefs).when(statements).getDef();
+
+    Set<String> parentExpressions = new HashSet<>();
+    IncludeDef includeDef1 = mock(IncludeDef.class);
+    List<IncludeDef> includeDefs = List.of(includeDef1);
+    doReturn(includeDefs).when(includes).getDef();
+    doReturn("SupplementalDataElements").when(includeDef1).getPath();
+    CompiledLibrary sdeCompiledLib = mock(CompiledLibrary.class);
+    Library sdeLib = mock(Library.class);
+    doReturn(sdeLib).when(sdeCompiledLib).getLibrary();
+    VersionedIdentifier sdeLibVersionedIdentifier = new VersionedIdentifier();
+    sdeLibVersionedIdentifier.setId("SupplementalDataElements");
+    doReturn(sdeLibVersionedIdentifier).when(sdeCompiledLib).getIdentifier();
+
+    Library.Statements statements1 = mock(Library.Statements.class);
+    doReturn(statements1).when(sdeLib).getStatements();
+    Library.Parameters parameters1 = mock(Library.Parameters.class);
+    doReturn(parameters1).when(sdeLib).getParameters();
+
+    doReturn(sdeCompiledLib).when(compiledLibraryMap).get(anyString());
+
+    CQLTools cqlTools =
+        new CQLTools(cqlData, null, parentExpressions, cqlTranslator, compiledLibraryMap);
+    assertNotNull(cqlTools);
+    try {
+      cqlTools.generate();
+      Set<DefinitionContent> contents = cqlTools.getDefinitionContents();
+      assertNotNull(contents);
+      Map<String, String> expressionToReturnTypeMap = cqlTools.getExpressionToReturnTypeMap();
+      assertThat(expressionToReturnTypeMap, is(notNullValue()));
+      assertThat(expressionToReturnTypeMap.containsKey("expression1"), is(true));
+      assertThat(expressionToReturnTypeMap.containsKey("expression2"), is(true));
+      assertThat(expressionToReturnTypeMap.get("expression1"), is(equalTo("System.Boolean")));
+      assertThat(expressionToReturnTypeMap.get("expression2"), is(nullValue()));
+    } catch (IOException e) {
+      fail();
+    }
+  }
 }
diff --git a/src/test/resources/tooling_test_qicore6.cql b/src/test/resources/tooling_test_qicore6.cql
new file mode 100644
index 0000000..e2aaf9a
--- /dev/null
+++ b/src/test/resources/tooling_test_qicore6.cql
@@ -0,0 +1,61 @@
+library QM61 version '0.0.000'
+
+using QICore version '6.0.0'
+
+include QICoreCommon version '3.0.000' called QICoreCommon
+include FHIRHelpers version '4.4.000' called FHIRHelpers
+include SupplementalDataElements version '4.3.000' called SDE
+include Hospice version '7.0.000' called Hospice
+include Status version '2.0.000' called Status
+
+codesystem "LOINC": 'http://loinc.org'
+codesystem "SNOMEDCT": 'http://snomed.info/sct'
+
+valueset "Clinical Oral Evaluation": 'http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113883.3.464.1003.125.12.1003'
+valueset "Dental Caries": 'http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113883.3.464.1003.125.12.1004'
+valueset "Discharged to Health Care Facility for Hospice Care": 'http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113883.3.117.1.7.1.207'
+valueset "Discharged to Home for Hospice Care": 'http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113883.3.117.1.7.1.209'
+valueset "Encounter Inpatient": 'http://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113883.3.666.5.307'
+
+code "Discharge to healthcare facility for hospice care (procedure)": '428371000124100' from "SNOMEDCT" display 'Discharge to healthcare facility for hospice care (procedure)'
+code "Discharge to home for hospice care (procedure)": '428361000124107' from "SNOMEDCT" display 'Discharge to home for hospice care (procedure)'
+code "Hospice care [Minimum Data Set]": '45755-6' from "LOINC" display 'Hospice care [Minimum Data Set]'
+code "Yes (qualifier value)": '373066001' from "SNOMEDCT" display 'Yes (qualifier value)'
+
+parameter "Measurement Period" Interval<DateTime>
+
+context Patient
+
+
+define "Initial Population":
+    AgeInYearsAt(date from start of "Measurement Period")in Interval[1, 20]
+        and exists ( "Qualifying Encounters" )
+
+define "Qualifying Encounters":
+    (([Encounter: "Clinical Oral Evaluation"]).isEncounterPerformed()) ValidEncounter
+        where ValidEncounter.period.toInterval() during day of "Measurement Period"
+
+define "Denominator":
+  "Initial Population"
+
+define "Denominator Exclusions":
+    Hospice."Has Hospice Services"
+
+define "Numerator":
+exists ["QICore Condition Problems Health Concerns": "Dental Caries"] DentalCaries
+        where DentalCaries.prevalenceInterval() overlaps "Measurement Period"
+
+define "SDE Ethnicity":
+  SDE."SDE Ethnicity"
+
+define "SDE Payer":
+  SDE."SDE Payer"
+
+define "SDE Race":
+  SDE."SDE Race"
+
+define "SDE Sex":
+  SDE."SDE Sex"
+
+define "SDE Eth":
+  SDE."SDE Eth"