diff --git a/app/graphql/types/query_type.rb b/app/graphql/types/query_type.rb
index b424ca4..573844c 100644
--- a/app/graphql/types/query_type.rb
+++ b/app/graphql/types/query_type.rb
@@ -59,6 +59,9 @@ def record_id(id:, index:)
                                             'you with one for your specific use case'
 
       argument :source, String, required: false, default_value: 'All', deprecation_reason: 'Use `sourceFilter`'
+      argument :boolean_type, String, required: false, default_value: 'OR',
+                                      description: 'How to join multiword queries. Defaults to "OR" which means any ' \
+                                                   'of the words much match. Options include: "OR", "AND"'
 
       # applied filters
       argument :access_to_files_filter, [String],
@@ -96,9 +99,9 @@ def record_id(id:, index:)
     end
 
     def search(searchterm:, citation:, contributors:, funding_information:, geodistance:, geobox:, identifiers:,
-               locations:, subjects:, title:, index:, source:, from:, **filters)
+               locations:, subjects:, title:, index:, source:, from:, boolean_type:, **filters)
       query = construct_query(searchterm, citation, contributors, funding_information, geodistance, geobox, identifiers,
-                              locations, subjects, title, source, filters)
+                              locations, subjects, title, source, boolean_type, filters)
 
       results = Opensearch.new.search(from, query, Timdex::OSClient, highlight_requested?, index)
 
@@ -128,9 +131,10 @@ def inject_hits_fields_into_source(hits)
     end
 
     def construct_query(searchterm, citation, contributors, funding_information, geodistance, geobox, identifiers,
-                        locations, subjects, title, source, filters)
+                        locations, subjects, title, source, boolean_type, filters)
       query = {}
       query[:q] = searchterm
+      query[:boolean_type] = boolean_type
       query[:citation] = citation
       query[:contributors] = contributors
       query[:funding_information] = funding_information
diff --git a/app/models/opensearch.rb b/app/models/opensearch.rb
index 48b97be..996def4 100644
--- a/app/models/opensearch.rb
+++ b/app/models/opensearch.rb
@@ -105,6 +105,33 @@ def multisearch
     ]
   end
 
+  # https://opensearch.org/docs/latest/query-dsl/minimum-should-match/#valid-values
+  # checks for preconfigured cases or uses whatever is supplied (i.e. we currently accept OpenSearch syntax for
+  # minimum_should_match)
+  def minimum_should_match
+    case @params[:boolean_type]
+    when 'OR'
+      '0%'
+    when 'AND'
+      '100%'
+    # 5 or less terms match all (AND)
+    # More than 5 match all but one
+    when 'experiment_a'
+      '4<100% 5<-1'
+    # 4 or less terms match all (AND)
+    # More than 4 match all but one
+    when 'experiment_b'
+      '3<100% 4<-1'
+    # 4 or less terms match all (AND)
+    # 5 to 10 match all but one
+    # 10 or more match 90%
+    when 'experiment_c'
+      '3<100% 9<-1 10<90%'
+    else
+      @params[:boolean_type]
+    end
+  end
+
   def matches
     m = []
     if @params[:q].present?
@@ -113,7 +140,8 @@ def matches
           query: @params[:q].downcase,
           fields: ['alternate_titles', 'call_numbers', 'citation', 'contents', 'contributors.value', 'dates.value',
                    'edition', 'funding_information.*', 'identifiers.value', 'languages', 'locations.value',
-                   'notes.value', 'numbering', 'publication_information', 'subjects.value', 'summary', 'title']
+                   'notes.value', 'numbering', 'publication_information', 'subjects.value', 'summary', 'title'],
+          minimum_should_match:
         }
       }
     end