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

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

.. code-block:: python

    >>> import pandas as pd
    >>> 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 -0.161152 -0.242498
    2       3 -1.107651  0.037718
    3       4 -2.158951 -1.220065
    4       5 -1.570458 -1.096670
