diff --git a/ctapipe/tools/train_disp_reconstructor.py b/ctapipe/tools/train_disp_reconstructor.py
index ec69a3d13b8..6b3ad6d0314 100644
--- a/ctapipe/tools/train_disp_reconstructor.py
+++ b/ctapipe/tools/train_disp_reconstructor.py
@@ -168,7 +168,7 @@ def _read_table(self, telescope_type):
 
             valid = check_valid_rows(table_chunk)
             if not np.all(valid):
-                n_non_predictable += np.sum(valid)
+                n_non_predictable += np.sum(~valid)
                 table_chunk = table_chunk[valid]
 
             table.append(table_chunk)
diff --git a/ctapipe/tools/train_energy_regressor.py b/ctapipe/tools/train_energy_regressor.py
index 3032e9237b3..7fe7986b380 100644
--- a/ctapipe/tools/train_energy_regressor.py
+++ b/ctapipe/tools/train_energy_regressor.py
@@ -151,7 +151,7 @@ def _read_table(self, telescope_type):
 
             valid = check_valid_rows(table_chunk)
             if not np.all(valid):
-                n_non_predictable += np.sum(valid)
+                n_non_predictable += np.sum(~valid)
                 table_chunk = table_chunk[valid]
 
             table.append(table_chunk)
diff --git a/ctapipe/tools/train_particle_classifier.py b/ctapipe/tools/train_particle_classifier.py
index d3d1d8074db..76865cd5366 100644
--- a/ctapipe/tools/train_particle_classifier.py
+++ b/ctapipe/tools/train_particle_classifier.py
@@ -202,7 +202,7 @@ def _read_table(self, telescope_type, loader, n_events=None):
 
             valid = check_valid_rows(table_chunk)
             if not np.all(valid):
-                n_non_predictable += np.sum(valid)
+                n_non_predictable += np.sum(~valid)
                 table_chunk = table_chunk[valid]
 
             table.append(table_chunk)