diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index f3a10c6dc..fa0c784a3 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -4,7 +4,7 @@ ci:
 
 repos:
 -   repo: https://github.com/psf/black
-    rev: 23.11.0
+    rev: 23.10.1
     hooks:
       - id: black-jupyter
 -   repo: https://github.com/asottile/pyupgrade
diff --git a/ema_workbench/analysis/prim.py b/ema_workbench/analysis/prim.py
index 5c6a1c279..2faa75a4a 100644
--- a/ema_workbench/analysis/prim.py
+++ b/ema_workbench/analysis/prim.py
@@ -362,6 +362,8 @@ def __init__(self, prim, box_lims, indices):
             "res_dim": pd.Series(dtype=int),
             "mass": pd.Series(dtype=float),
             "id": pd.Series(dtype=int),
+            "n": pd.Series(dtype=int),  # items in box
+            "k": pd.Series(dtype=int),  # items of interest in box
         }
 
         self.peeling_trajectory = pd.DataFrame(columns)
@@ -796,6 +798,8 @@ def update(self, box_lims, indices):
             "res_dim": restricted_dims.shape[0],
             "mass": y.shape[0] / self.prim.n,
             "id": i,
+            "n": y.shape[0],
+            "k": coi,
         }
         new_row = pd.DataFrame([data])
         # self.peeling_trajectory = self.peeling_trajectory.append(
@@ -872,7 +876,7 @@ def show_pairs_scatter(
         if dims is None:
             dims = sdutil._determine_restricted_dims(self.box_lims[i], self.prim.box_init)
 
-        if diag_kind not in diag_kind.__members__:
+        if diag_kind not in DiagKind:
             raise ValueError(
                 f"diag_kind should be one of DiagKind.KDE or DiagKind.CDF, not {diag_kind}"
             )
@@ -916,10 +920,10 @@ def _calculate_quasi_p(self, i, restricted_dims):
         box_lim = box_lim[restricted_dims]
 
         # total nr. of cases in box
-        Tbox = self.peeling_trajectory["mass"][i] * self.prim.n
+        Tbox = self.peeling_trajectory.loc[i, "n"]
 
         # total nr. of cases of interest in box
-        Hbox = self.peeling_trajectory["coverage"][i] * self.prim.t_coi
+        Hbox = self.peeling_trajectory.loc[i, "k"]
 
         x = self.prim.x.loc[self.prim.yi_remaining, restricted_dims]
         y = self.prim.y[self.prim.yi_remaining]
diff --git a/ema_workbench/analysis/prim_util.py b/ema_workbench/analysis/prim_util.py
index f6b3c709c..0d321ca42 100644
--- a/ema_workbench/analysis/prim_util.py
+++ b/ema_workbench/analysis/prim_util.py
@@ -37,6 +37,9 @@ class DiagKind(Enum):
     CDF = "cdf"
     """constant for plotting diagonal in pairs_scatter as cdf"""
 
+    def __contains__(cls, item):
+        return item in cls.__members__.values()
+
 
 def get_quantile(data, quantile):
     """
diff --git a/test/test_analysis/test_prim.py b/test/test_analysis/test_prim.py
index 1c249b856..ffd096af6 100644
--- a/test/test_analysis/test_prim.py
+++ b/test/test_analysis/test_prim.py
@@ -38,7 +38,7 @@ def test_init(self):
         prim_obj = prim.setup_prim(results, "y", threshold=0.8)
         box = PrimBox(prim_obj, prim_obj.box_init, prim_obj.yi)
 
-        self.assertEqual(box.peeling_trajectory.shape, (1, 6))
+        self.assertEqual(box.peeling_trajectory.shape, (1, 8))
 
     def test_select(self):
         x = pd.DataFrame([(0, 1, 2), (2, 5, 6), (3, 2, 1)], columns=["a", "b", "c"])