diff --git a/run_data_analysis/src/run_data_analysis/core.py b/run_data_analysis/src/run_data_analysis/core.py
new file mode 100644
index 0000000..d82a702
--- /dev/null
+++ b/run_data_analysis/src/run_data_analysis/core.py
@@ -0,0 +1,61 @@
+from __future__ import annotations
+
+import json
+from dataclasses import dataclass, asdict
+from typing import Dict, Any
+import pandas as pd
+import statistics
+
+
+@dataclass
+class RunData:
+    """Repräsentiert Messdaten eines einzelnen Runs zur Bandanalyse."""
+
+    band_center: float
+    band_width: float
+    cluster_score: float
+    retry_tail: float
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> RunData:
+        required_fields = {"band_center", "band_width", "cluster_score", "retry_tail"}
+        missing = required_fields - data.keys()
+        if missing:
+            raise ValueError(f"Missing fields in RunData: {missing}")
+
+        try:
+            return cls(
+                band_center=float(data["band_center"]),
+                band_width=float(data["band_width"]),
+                cluster_score=float(data["cluster_score"]),
+                retry_tail=float(data["retry_tail"]),
+            )
+        except (TypeError, ValueError) as e:
+            raise ValueError(f"Invalid data types in RunData: {e}") from e
+
+
+def analyse_run_data(run_data: RunData) -> Dict[str, Any]:
+    """Analysiert Run-Daten, um statistische Kennzahlen zum Resonanzband zu berechnen."""
+
+    assert isinstance(run_data, RunData), "Input must be a RunData instance"
+
+    # Form DataFrame for flexibility and possible extension to multiple runs
+    data = pd.DataFrame([asdict(run_data)])
+
+    # Calculate basic stats using pandas and statistics for robustness
+    result = {
+        "band_center_mean": data["band_center"].mean(),
+        "band_width_mean": data["band_width"].mean(),
+        "cluster_score_mean": data["cluster_score"].mean(),
+        "retry_tail_mean": data["retry_tail"].mean(),
+        "band_center_std": float(statistics.pstdev(data["band_center"])) if len(data) > 1 else 0.0,
+        "band_width_std": float(statistics.pstdev(data["band_width"])) if len(data) > 1 else 0.0,
+        "stability_index": float(run_data.cluster_score / max(run_data.band_width, 1e-9)),
+        "retry_tail_ratio": float(run_data.retry_tail / max(run_data.cluster_score, 1e-9)),
+    }
+
+    # Validation for CI readiness
+    for key, value in result.items():
+        assert isinstance(value, float), f"Value for {key} must be float"
+
+    return result