diff --git a/public/components/query_compare/search_result/index.tsx b/public/components/query_compare/search_result/index.tsx
index e9a65d3..d5573b8 100644
--- a/public/components/query_compare/search_result/index.tsx
+++ b/public/components/query_compare/search_result/index.tsx
@@ -11,7 +11,7 @@ import { SearchConfigsPanel } from './search_components/search_configs/search_co
 import { SearchInputBar } from './search_components/search_bar';
 import { ServiceEndpoints } from '../../../../common';
 import { Header } from '../../common/header';
-import { SearchResults, QueryError, QueryStringError } from '../../../types/index';
+import { SearchResults, QueryError, QueryStringError, SelectIndexError } from '../../../types/index';
 import { ResultComponents } from './result_components/result_components';
 import { useSearchRelevanceContext, initialQueryErrorState } from '../../../contexts';
 
@@ -53,7 +53,7 @@ export const SearchResult = ({ http }: SearchResultProps) => {
   const validateQuery = (selectedIndex: string, queryString: string, queryError: QueryError) => {
     // Check if select an index
     if (!selectedIndex.length) {
-      queryError.selectIndex = 'An index is required. Select an index.';
+      queryError.selectIndex = SelectIndexError.unselected;
     }
 
     // Check if query string is empty
diff --git a/public/components/query_compare/search_result/search_components/search_configs/search_config.tsx b/public/components/query_compare/search_result/search_components/search_configs/search_config.tsx
index 8f98e55..5fc8cd1 100644
--- a/public/components/query_compare/search_result/search_components/search_configs/search_config.tsx
+++ b/public/components/query_compare/search_result/search_components/search_configs/search_config.tsx
@@ -15,7 +15,7 @@ import {
 } from '@elastic/eui';
 
 import { useSearchRelevanceContext } from '../../../../../contexts';
-import { QueryError, QueryStringError } from '../../../../../types/index';
+import { QueryError, QueryStringError, SelectIndexError } from '../../../../../types/index';
 
 interface SearchConfigProps {
   queryNumber: 1 | 2;
@@ -54,7 +54,7 @@ export const SearchConfig: FunctionComponent<SearchConfigProps> = ({
     if (!selectedIndex.length) {
       setQueryError({
         ...queryError,
-        selectIndex: 'An index is required. Select an index.',
+        selectIndex: SelectIndexError.unselected,
       });
     }
   };
diff --git a/public/types/index.ts b/public/types/index.ts
index 865ec41..e1dbffe 100644
--- a/public/types/index.ts
+++ b/public/types/index.ts
@@ -45,12 +45,16 @@ export interface SearchResults {
   };
 }
 
+export enum SelectIndexError {
+  unselected = 'An index is required to compare search results. Select an index.'
+}
+
 export enum QueryStringError {
   empty = 'A query is required. Enter a query.',
   invalid = 'Query syntax is invalid. Enter a valid query.',
 }
 
 export interface QueryError {
-  selectIndex: 'An index is required. Select an index.' | '';
+  selectIndex: SelectIndexError | string;
   queryString: QueryStringError | string;
 }