diff --git a/glue/sample/src/sinter/_decoding/_stim_then_decode_sampler.py b/glue/sample/src/sinter/_decoding/_stim_then_decode_sampler.py
index ee28c53e..c9a70268 100755
--- a/glue/sample/src/sinter/_decoding/_stim_then_decode_sampler.py
+++ b/glue/sample/src/sinter/_decoding/_stim_then_decode_sampler.py
@@ -197,8 +197,8 @@ def sample(self, max_shots: int) -> AnonTaskStats:
             raise ValueError("predictions.dtype != np.uint8")
         if len(predictions.shape) != 2:
             raise ValueError("len(predictions.shape) != 2")
-        if predictions.shape[0] != num_shots:
-            raise ValueError("predictions.shape[0] != num_shots")
+        if predictions.shape[0] != num_shots - num_discards_1:
+            raise ValueError("predictions.shape[0] != num_shots - num_discards_1")
         if predictions.shape[1] < actual_obs.shape[1]:
             raise ValueError("predictions.shape[1] < actual_obs.shape[1]")
         if predictions.shape[1] > actual_obs.shape[1] + 1: