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What's a Fair Rent for This Munich Flat?

From living area, year built, location, bathroom, kitchen, heating and district, what net rent does this flat command? Munich's rent index is built from exactly this kind of table.

Use caseFinancePredictionModel evaluation

The table

3,082 Munich flats from the 1999 rent index survey with size, year built, location quality, fittings and district, and the net rent. It's in Welt's research catalogue as Munich Rent Index (1999) Apartments, 3,082 rows by 9 columns, licensed CC0: Public Domain. The catalogue measures its signal at 0.45. At 3,082 rows and 8 features, TabICLv2, Kumo Tabular Medium and Mitra-v2 take the table as it is. The others can't take a table this size, so the walkthrough leaves them out.

Walkthrough

  1. Load it from the catalogue

    Find the table, read its recorded target and print the column names.

    import pandas as pd
    from welt import Client
    
    with Client() as client:
        item = client.research_datasets(q="Munich rent index", limit=1)["items"][0]
        info = client.research_dataset(item["id"])
        data = client.load_research_dataset(item["id"])
    
    target = info["targets"][0]
    target = target["name"] if isinstance(target, dict) else target
    print([column["name"] for column in info["schema"]], target)
  2. Pick the rows

    Set aside 20 rows to predict at the end, and keep the rest for the models to learn from.

    known = data.dropna(subset=[target])
    new_rows = known.sample(20, random_state=1)
    table = known.drop(new_rows.index)
  3. Compare the models and predict

    The models compete on the same folds against a simple guess, then the top-ranked one is fitted on the whole table. RMSE and MAE are average errors in the target's own units, so lower is better. The last table puts each prediction next to the real answer.

    with Client() as client:
        evaluation = client.evaluate(table, target, task="regression", seed=7,
                                     models=["tabicl-v2", "kumo-medium", "mitra-v2"])
        model = evaluation.fit()
    
    print(evaluation.summary()[["name", "rank", "rmse_mean", "mae_mean"]])
    features = new_rows.drop(columns=target)
    print(pd.DataFrame({"actual": new_rows[target].values, "predicted": model.predict(features)}))

What you get

A rent estimateFor any flat in the table.
Above or below the indexCompare the estimate with the rent charged.
A well-known tableUsed in statistics teaching for decades.

Try it

Use Open with to run the research datasets notebook in Colab, Kaggle or Jupyter and search for "Munich rent index", or run the code above after pip install "welt-client[parquet]".