diff --git a/judges/latest-assessment/latest-assessment.rb b/judges/latest-assessment/latest-assessment.rb
index b4cbe510..7fef631a 100644
--- a/judges/latest-assessment/latest-assessment.rb
+++ b/judges/latest-assessment/latest-assessment.rb
@@ -9,10 +9,10 @@
   assessments = fb.query('(and (eq what "assessment") (exists text) (exists when))').each.to_a
   fb.query('(eq what "latest-assessment")').delete!
   next if assessments.empty?
-  latest = assessments.max_by(&:when)
+  latest = assessments.max_by { |assessment| assessment['when'].min }
   f = fb.insert
   f.what = 'latest-assessment'
   f.text = latest.text
-  f.when = latest.when
+  f.when = latest['when'].min
   f.total = assessments.size
 end
diff --git a/test/pages/test_latest_assessment.rb b/test/pages/test_latest_assessment.rb
index 4da57c34..c41bdf5a 100644
--- a/test/pages/test_latest_assessment.rb
+++ b/test/pages/test_latest_assessment.rb
@@ -27,6 +27,25 @@ def test_replaces_previous_summary
     assert_equal(1, latest.first.total)
   end
 
+  def test_uses_earliest_value_when_comparing_multi_valued_dates
+    fb = Factbase.new
+    first = fb.insert
+    first._id = 1
+    first.what = 'assessment'
+    first.text = 'Earlier effective date'
+    first.when = Time.utc(2025, 1, 1)
+    first.when = Time.utc(2024, 1, 1)
+    second = fb.insert
+    second._id = 2
+    second.what = 'assessment'
+    second.text = 'Latest effective date'
+    second.when = Time.utc(2024, 6, 1)
+    load_it('latest-assessment', fb)
+    latest = fb.query('(eq what "latest-assessment")').each.to_a.fetch(0)
+    assert_equal('Latest effective date', latest.text)
+    assert_equal(Time.utc(2024, 6, 1), latest.when)
+  end
+
   private
 
   def assessment_factbase