Revision Metrics
================

Revision metrics assess how index values change as new data becomes available:

.. code-block:: python

    >>> from hpipy.datasets import load_seattle_sales
    >>> from hpipy.price_index import RepeatTransactionIndex
    >>> from hpipy.utils.metrics import revision

    >>> df = load_seattle_sales()

    >>> hpi = RepeatTransactionIndex.create_index(
    ...     trans_data=df,
    ...     prop_id="pinx",
    ...     trans_id="sale_id",
    ...     price="sale_price",
    ...     date="sale_date",
    ...     periodicity="M",
    ...     estimator="robust",
    ...     log_dep=True,
    ...     smooth=True,
    ... )

    >>> hpi_series = hpi.create_series(train_period=24, max_period=30)

    >>> rev = revision(hpi_series)
    >>> rev.head()
       period      mean    median
    0       1  0.000000  0.000000
    1       2 -0.161268 -0.242763
    2       3 -1.107773  0.037327
    3       4 -2.159030 -1.220268
    4       5 -1.570491 -1.096907
