diff --git a/icu_benchmarks/data/preprocessor.py b/icu_benchmarks/data/preprocessor.py
index 27f847cb..a00303b5 100644
--- a/icu_benchmarks/data/preprocessor.py
+++ b/icu_benchmarks/data/preprocessor.py
@@ -82,41 +82,55 @@ def apply(self, data, vars) -> dict[dict[pl.DataFrame]]:
         Returns:
             Preprocessed data.
         """
-        logging.info("Preprocessing dynamic features.")
-
-        data = self._process_dynamic(data, vars)
-        if self.use_static_features and len(vars[Segment.static]) > 0:
+        # Check if dynamic features are present
+        if self.use_static_features and all(Segment.static in value for value in data.values()) and len(vars[Segment.static]) > 0:
             logging.info("Preprocessing static features.")
             data = self._process_static(data, vars)
+        else:
+            self.use_static_features = False
+
+        if all(Segment.dynamic in value for value in data.values()):
+            logging.info("Preprocessing dynamic features.")
+            logging.info(data.keys())
+            data = self._process_dynamic(data, vars)
+            if self.use_static_features:
+                # Join static and dynamic data.
+                data[Split.train][Segment.dynamic] = data[Split.train][Segment.dynamic].join(
+                    data[Split.train][Segment.static], on=vars["GROUP"]
+                )
+                data[Split.val][Segment.dynamic] = data[Split.val][Segment.dynamic].join(
+                    data[Split.val][Segment.static], on=vars["GROUP"]
+                )
+                data[Split.test][Segment.dynamic] = data[Split.test][Segment.dynamic].join(
+                    data[Split.test][Segment.static], on=vars["GROUP"]
+                )
 
-            # Set index to grouping variable
-            data[Split.train][Segment.static] = data[Split.train][Segment.static]#.set_index(vars["GROUP"])
-            data[Split.val][Segment.static] = data[Split.val][Segment.static]#.set_index(vars["GROUP"])
-            data[Split.test][Segment.static] = data[Split.test][Segment.static]#.set_index(vars["GROUP"])
+                # Remove static features from splits
+                data[Split.train][Segment.features] = data[Split.train].pop(Segment.static)
+                data[Split.val][Segment.features] = data[Split.val].pop(Segment.static)
+                data[Split.test][Segment.features] = data[Split.test].pop(Segment.static)
 
-            # Join static and dynamic data.
-            data[Split.train][Segment.dynamic] = data[Split.train][Segment.dynamic].join(
-                data[Split.train][Segment.static], on=vars["GROUP"]
-            )
-            data[Split.val][Segment.dynamic] = data[Split.val][Segment.dynamic].join(
-                data[Split.val][Segment.static], on=vars["GROUP"]
-            )
-            data[Split.test][Segment.dynamic] = data[Split.test][Segment.dynamic].join(
-                data[Split.test][Segment.static], on=vars["GROUP"]
-            )
-
-            # Remove static features from splits
+            # Create feature splits
+            data[Split.train][Segment.features] = data[Split.train].pop(Segment.dynamic)
+            data[Split.val][Segment.features] = data[Split.val].pop(Segment.dynamic)
+            data[Split.test][Segment.features] = data[Split.test].pop(Segment.dynamic)
+        elif self.use_static_features:
             data[Split.train][Segment.features] = data[Split.train].pop(Segment.static)
             data[Split.val][Segment.features] = data[Split.val].pop(Segment.static)
             data[Split.test][Segment.features] = data[Split.test].pop(Segment.static)
-
-        # Create feature splits
-        data[Split.train][Segment.features] = data[Split.train].pop(Segment.dynamic)
-        data[Split.val][Segment.features] = data[Split.val].pop(Segment.dynamic)
-        data[Split.test][Segment.features] = data[Split.test].pop(Segment.dynamic)
-
+        else:
+            raise Exception(f"No recognized data segments data to preprocess. Available: {data.keys()}")
         logging.debug("Data head")
         logging.debug(data[Split.train][Segment.features].head())
+        logging.debug(data[Split.train][Segment.outcome])
+        for split in [Split.train, Split.val, Split.test]:
+            if vars["SEQUENCE"] in data[split][Segment.outcome] and len(data[split][Segment.features]) != len(data[split][Segment.outcome]):
+                raise Exception(f"Data and outcome length mismatch in {split} split: "
+                                f"features: {len(data[split][Segment.features])}, outcome: {len(data[split][Segment.outcome])}")
+        data[Split.train][Segment.features] = data[Split.train][Segment.features].unique()
+        data[Split.val][Segment.features] = data[Split.val][Segment.features].unique()
+        data[Split.test][Segment.features] = data[Split.test][Segment.features].unique()
+
         logging.info(f"Generate features: {self.generate_features}")
         return data
 
@@ -321,6 +335,7 @@ def apply(self, data, vars) -> dict[dict[pd.DataFrame]]:
 
         logging.debug("Data head")
         logging.debug(data[Split.train][Segment.features].head())
+        logging.debug(data[Split.train][Segment.outcome].head())
         logging.info(f"Generate features: {self.generate_features}")
         return data