Remove eigenbedarf_gedeckt from Kindergeldübertrag (#786)

Closes #758

Author: MImmesberger

CHANGES.md

@@ -6,6 +6,8 @@ releases are available on [Anaconda.org](https://anaconda.org/conda-forge/gettsi
 
 ## Unpublished
 
+- {gh}`786` Check directly whether child and parent are in same Bedarfsgemeinschaft for
+  Kindergeldübertrag ({ghuser}`MImmesberger`).
 - {gh}`785` Add NotImplementedError to Unterhaltsvorschuss and test whether output from
   `create_synthetic_data` is enough to compute default targets ({ghuser}`MImmesberger`).
 - {gh}`772` Add Mindesteinkommen check to Wohngeld, calculate anz_eig_kind_bis_24

src/_gettsim/config.py

@@ -158,6 +158,9 @@ def set_array_backend(backend: str):
     "p_id_einstandspartner": int,
     "vermögen_bedürft": float,
     "eigenbedarf_gedeckt": bool,
+    # TODO(@MImmesberger): Remove input variable eigenbedarf_gedeckt once
+    # Bedarfsgemeinschaften are fully endogenous
+    # https://github.com/iza-institute-of-labor-economics/gettsim/issues/763
     "gemeinsam_veranlagt": bool,
     "bruttolohn_m": float,
     "alter": int,

src/_gettsim/groupings.py

@@ -23,6 +23,9 @@ def bg_id_numpy(
     """
     Compute the ID of the Bedarfsgemeinschaft for each person.
     """
+    # TODO(@MImmesberger): Remove input variable eigenbedarf_gedeckt once
+    # Bedarfsgemeinschaften are fully endogenous
+    # https://github.com/iza-institute-of-labor-economics/gettsim/issues/763
     counter = Counter()
     result = []
 

src/_gettsim/transfers/arbeitsl_geld_2/kindergelduebertrag.py

@@ -108,7 +108,7 @@ def _diff_kindergeld_kindbedarf_m(  # noqa: PLR0913
     kindergeld_zur_bedarfsdeckung_m: float,
     kind_unterh_erhalt_m: float,
     unterhaltsvors_m: float,
-    eigenbedarf_gedeckt: bool,
+    _in_anderer_bedarfsgemeinschaft_als_kindergeldempfänger: bool,
 ) -> float:
     """Kindergeld that is used to cover the needs (SGB II) of the parent.
 
@@ -133,19 +133,13 @@ def _diff_kindergeld_kindbedarf_m(  # noqa: PLR0913
         See :func:`kind_unterh_erhalt_m`.
     unterhaltsvors_m
         See :func:`unterhaltsvors_m`.
-    eigenbedarf_gedeckt
-        See :func:`eigenbedarf_gedeckt`.
+    _in_anderer_bedarfsgemeinschaft_als_kindergeldempfänger
+        See :func:`_in_anderer_bedarfsgemeinschaft_als_kindergeldempfänger`.
 
     Returns
     -------
 
     """
-    # TODO (@MImmesberger): Remove `eigenbedarf_gedeckt` conditions once
-    # Bedarfsgemeinschaft is fully endogenous. This is a temporary fix. Without it,
-    # Kindergeld would be counted twice as income of the Bedarfsgemeinschaft (one time
-    # the full amount for the child and one time the Kindergeldübertrag for the parent -
-    # because the child doesn't drop out of Bedarfsgemeinschaft endogenously).
-    # https://github.com/iza-institute-of-labor-economics/gettsim/issues/758
     fehlbetrag = max(
         arbeitsl_geld_2_regelbedarf_m_bg
         - wohngeld_anspruchshöhe_m_bg
@@ -155,9 +149,47 @@ def _diff_kindergeld_kindbedarf_m(  # noqa: PLR0913
         0.0,
     )
     # Bedarf not covered or same Bedarfsgemeinschaft as parents
-    if not eigenbedarf_gedeckt or fehlbetrag > kindergeld_zur_bedarfsdeckung_m:
+    if (
+        not _in_anderer_bedarfsgemeinschaft_als_kindergeldempfänger
+        or fehlbetrag > kindergeld_zur_bedarfsdeckung_m
+    ):
         out = 0.0
     # Bedarf is covered
     else:
         out = kindergeld_zur_bedarfsdeckung_m - fehlbetrag
     return out
+
+
+@policy_info(skip_vectorization=True)
+def _in_anderer_bedarfsgemeinschaft_als_kindergeldempfänger(
+    p_id: numpy.ndarray[int],
+    p_id_kindergeld_empf: numpy.ndarray[int],
+    bg_id: numpy.ndarray[int],
+) -> numpy.ndarray[bool]:
+    """True if the person is in a different Bedarfsgemeinschaft than the
+    Kindergeldempfänger of that person.
+
+    Parameters
+    ----------
+    p_id
+        See basic input variable :ref:`p_id <p_id>`
+    p_id_kindergeld_empf
+        See basic input variable :ref:`p_id_kindergeld_empf <p_id_kindergeld_empf>`
+    bg_id
+        See :func:`bg_id`.
+
+    Returns
+    -------
+
+    """
+    # Create a dictionary to map p_id to bg_id
+    p_id_to_bg_id = dict(zip(p_id, bg_id))
+
+    # Map each p_id_kindergeld_empf to its corresponding bg_id
+    empf_bg_id = [
+        p_id_to_bg_id[empfänger_id] if empfänger_id >= 0 else -1
+        for empfänger_id in p_id_kindergeld_empf
+    ]
+
+    # Compare bg_id array with the mapped bg_ids of p_id_kindergeld_empf
+    return bg_id != empf_bg_id

src/_gettsim_tests/test_data/arbeitsl_geld_2/2024/alleinerz_kein_kindergelduebertrag.yaml

@@ -38,13 +38,6 @@ inputs:
       - false
       - false
       - false
-    eigenbedarf_gedeckt:
-      - false
-      - false
-      - false
-    # TODO (@MImmesberger): Remove `eigenbedarf_gedeckt` conditions once
-    # Bedarfsgemeinschaft is fully endogenous. This is a temporary fix.
-    # https://github.com/iza-institute-of-labor-economics/gettsim/issues/622
     kind:
       - false
       - true
@@ -157,12 +150,12 @@ inputs:
       - false
       - false
       - false
-  assumed: {}
+  assumed:
+    bg_id:
+      - 0
+      - 0
+      - 0
 outputs:
-  bg_id:
-    - 0
-    - 0
-    - 0
   kindergeldübertrag_m:
     - 0.0
     - 0.0

src/_gettsim_tests/test_data/arbeitsl_geld_2/2024/alleinerz_teilw_kindergelduebertrag.yaml

@@ -40,13 +40,6 @@ inputs:
       - false
       - false
       - false
-    eigenbedarf_gedeckt:
-      - false
-      - false
-      - true
-    # TODO (@MImmesberger): Remove `eigenbedarf_gedeckt` conditions once
-    # Bedarfsgemeinschaft is fully endogenous. This is a temporary fix.
-    # https://github.com/iza-institute-of-labor-economics/gettsim/issues/622
     kind:
       - false
       - true

src/_gettsim_tests/test_data/arbeitsl_geld_2/2024/alleinerz_voller_kindergelduebertrag.yaml

@@ -40,13 +40,6 @@ inputs:
       - false
       - false
       - false
-    eigenbedarf_gedeckt:
-      - false
-      - false
-      - true
-    # TODO (@MImmesberger): Remove `eigenbedarf_gedeckt` conditions once
-    # Bedarfsgemeinschaft is fully endogenous. This is a temporary fix.
-    # https://github.com/iza-institute-of-labor-economics/gettsim/issues/622
     kind:
       - false
       - true
@@ -159,12 +152,12 @@ inputs:
       - false
       - false
       - false
-  assumed: {}
+  assumed:
+    bg_id:
+      - 0
+      - 0
+      - 1
 outputs:
-  bg_id:
-    - 0
-    - 0
-    - 1
   kindergeldübertrag_m:
     - 250.0
     - 0.0