diff --git a/package/MDAnalysis/analysis/polymer.py b/package/MDAnalysis/analysis/polymer.py
index 7a0510eab0..0d832d1198 100644
--- a/package/MDAnalysis/analysis/polymer.py
+++ b/package/MDAnalysis/analysis/polymer.py
@@ -317,7 +317,7 @@ def fit(self):
 
     def _conclude(self):
         norm = np.linspace(self.chainlength - 1, 1, self.chainlength - 1)
-        norm *= len(self._atomgroups) * self._trajectory.n_frames
+        norm *= len(self._atomgroups) * self.n_frames
         self.results.bond_autocorrelation = (
             self.results.raw_bond_autocorr / norm
         )
diff --git a/testsuite/MDAnalysisTests/analysis/test_persistencelength.py b/testsuite/MDAnalysisTests/analysis/test_persistencelength.py
index 54005c8a66..cd11071ee3 100644
--- a/testsuite/MDAnalysisTests/analysis/test_persistencelength.py
+++ b/testsuite/MDAnalysisTests/analysis/test_persistencelength.py
@@ -72,6 +72,10 @@ def test_ag_ValueError(self, u):
     def test_run(self, p_run):
         assert len(p_run.results.bond_autocorrelation) == 280
 
+    def test_run_partial(self, p):
+        p.run(start=0, stop=2)
+        assert_almost_equal(p.results.bond_autocorrelation[0], 1.0, 3)
+
     def test_lb(self, p_run):
         assert_almost_equal(p_run.results.lb, 1.485, 3)