From 972278d17910edf9285da88f9946f36785eb89b5 Mon Sep 17 00:00:00 2001
From: CamDavidsonPilon <cam.davidson.pilon@gmail.com>
Date: Thu, 20 Feb 2020 10:50:45 -0500
Subject: [PATCH] changelog

---
 CHANGELOG.md       |   2 +-
 docs/Changelog.rst | 448 ++++++++++++++++++++++++++-------------------
 2 files changed, 262 insertions(+), 188 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1fda8d228..18058898a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 ## Changelog
 
-#### 0.24.0 - unreleased
+#### 0.24.0 - 2020-02-20
 
 This version and future versions of lifelines no longer support py35. Pandas 1.0 is fully supported, along with previous version. Minimum Scipy has been bumped to 1.2.0
 
diff --git a/docs/Changelog.rst b/docs/Changelog.rst
index 3a0f63d54..3d95748d7 100644
--- a/docs/Changelog.rst
+++ b/docs/Changelog.rst
@@ -1,9 +1,79 @@
 Changelog
 ---------
 
+0.24.0 - 2020-02-20
+^^^^^^^^^^^^^^^^^^^
+
+This version and future versions of lifelines no longer support py35.
+Pandas 1.0 is fully supported, along with previous version. Minimum
+Scipy has been bumped to 1.2.0
+
+New features
+''''''''''''
+
+-  ``CoxPHFitter`` and ``CoxTimeVaryingFitter`` has support for an
+   elastic net penalty, which includes L1 and L2 regression.
+-  ``CoxPHFitter`` has new baseline survival estimation methods.
+   Specifically, ``spline`` now estimates the coefficients and baseline
+   survival using splines. The traditional method, ``breslow``, is still
+   the default however.
+-  Regression models have a new ``score`` method that will score your
+   model against a dataset (ex: a testing or validation dataset). The
+   default is to evaluate the log-likelihood, but also the concordance
+   index can be chose.
+-  New ``MixtureCureFitter`` for quickly creating univariate mixture
+   models.
+-  Univariate parametric models have a ``plot_density``,
+   ``density_at_times``, and property ``density_`` that computes the
+   probability density function estimates.
+-  new dataset for interval regression involving C. Botulinum.
+-  new ``lifelines.fitters.mixins.ProportionalHazardMixin`` that
+   implements proportional hazard checks.
+
+API Changes
+'''''''''''
+
+-  Models’ prediction method that return a single array now return a
+   Series (use to return a DataFrame). This includes ``predict_median``,
+   ``predict_percentile``, ``predict_expectation``,
+   ``predict_log_partial_hazard``, and possibly others.
+-  The penalty in Cox models is now scaled by the number of
+   observations. This makes it invariant to changing sample sizes. This
+   change also make the penalty magnitude behave the same as any
+   parametric regression model.
+-  ``score_`` on models has been renamed ``concordance_index_``
+-  models’ ``.variance_matrix_`` is now a DataFrame.
+-  ``CoxTimeVaryingFitter`` no longer requires an ``id_col``. It’s
+   optional, and some checks may be done for integrity if provided.
+-  Significant changes to ``utils.k_fold_cross_validation``.
+-  removed automatically adding ``inf`` from
+   ``PiecewiseExponentialRegressionFitter.breakpoints`` and
+   ``PiecewiseExponentialFitter.breakpoints``
+-  ``tie_method`` was dropped from Cox models (it was always Efron
+   anyways…)
+-  Mixins are moved to ``lifelines.fitters.mixins``
+-  ``find_best_parametric_model`` ``evaluation`` kwarg has been changed
+   to ``scoring_method``.
+-  removed ``_score_`` and ``path`` from Cox model.
+
+Bug fixes
+'''''''''
+
+-  Fixed ``show_censors`` with
+   ``KaplanMeierFitter.plot_cumulative_density`` see issue #940.
+-  Fixed error in ``"BIC"`` code path in ``find_best_parametric_model``
+-  Fixed a bug where left censoring in AFT models was not converging
+   well
+-  Cox models now incorporate any penalizers in their
+   ``log_likelihood_``
+
+.. _section-1:
+
 0.23.9 - 2020-01-28
 ^^^^^^^^^^^^^^^^^^^
 
+.. _bug-fixes-1:
+
 Bug fixes
 '''''''''
 
@@ -13,12 +83,12 @@ Bug fixes
    of ``GeneralizedGammaRegressionFitter`` and any custom regression
    models should update their code as soon as possible.
 
-.. _section-1:
+.. _section-2:
 
 0.23.8 - 2020-01-21
 ^^^^^^^^^^^^^^^^^^^
 
-.. _bug-fixes-1:
+.. _bug-fixes-2:
 
 Bug fixes
 '''''''''
@@ -29,18 +99,20 @@ Bug fixes
    ``GeneralizedGammaRegressionFitter`` and any custom regression models
    should update their code as soon as possible.
 
-.. _section-2:
+.. _section-3:
 
 0.23.7 - 2020-01-14
 ^^^^^^^^^^^^^^^^^^^
 
 Bug fixes for py3.5.
 
-.. _section-3:
+.. _section-4:
 
 0.23.6 - 2020-01-07
 ^^^^^^^^^^^^^^^^^^^
 
+.. _new-features-1:
+
 New features
 ''''''''''''
 
@@ -53,12 +125,12 @@ New features
 -  custom parametric regression models can now do left and interval
    censoring.
 
-.. _section-4:
+.. _section-5:
 
 0.23.5 - 2020-01-05
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-1:
+.. _new-features-2:
 
 New features
 ''''''''''''
@@ -67,7 +139,7 @@ New features
 -  New lymph node cancer dataset, originally from *H.F. for the German
    Breast Cancer Study Group (GBSG) (1994)*
 
-.. _bug-fixes-2:
+.. _bug-fixes-3:
 
 Bug fixes
 '''''''''
@@ -77,26 +149,26 @@ Bug fixes
 -  fixed bug where large exponential numbers in ``print_summary`` were
    not being suppressed correctly.
 
-.. _section-5:
+.. _section-6:
 
 0.23.4 - 2019-12-15
 ^^^^^^^^^^^^^^^^^^^
 
 -  Bug fix for PyPI
 
-.. _section-6:
+.. _section-7:
 
 0.23.3 - 2019-12-11
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-2:
+.. _new-features-3:
 
 New features
 ''''''''''''
 
 -  ``StatisticalResult.print_summary`` supports html output.
 
-.. _bug-fixes-3:
+.. _bug-fixes-4:
 
 Bug fixes
 '''''''''
@@ -104,12 +176,12 @@ Bug fixes
 -  fix import in ``printer.py``
 -  fix html printing with Univariate models.
 
-.. _section-7:
+.. _section-8:
 
 0.23.2 - 2019-12-07
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-3:
+.. _new-features-4:
 
 New features
 ''''''''''''
@@ -121,7 +193,7 @@ New features
 -  performance improvements on regression models’ preprocessing. Should
    make datasets with high number of columns more performant.
 
-.. _bug-fixes-4:
+.. _bug-fixes-5:
 
 Bug fixes
 '''''''''
@@ -130,12 +202,12 @@ Bug fixes
 -  fixed repr for ``sklearn_adapter`` classes.
 -  fixed ``conditional_after`` in Cox model with strata was used.
 
-.. _section-8:
+.. _section-9:
 
 0.23.1 - 2019-11-27
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-4:
+.. _new-features-5:
 
 New features
 ''''''''''''
@@ -145,7 +217,7 @@ New features
 -  performance improvements for ``CoxPHFitter`` - up to 30% performance
    improvements for some datasets.
 
-.. _bug-fixes-5:
+.. _bug-fixes-6:
 
 Bug fixes
 '''''''''
@@ -157,12 +229,12 @@ Bug fixes
 -  fixed bug when using ``print_summary`` with left censored models.
 -  lots of minor bug fixes.
 
-.. _section-9:
+.. _section-10:
 
 0.23.0 - 2019-11-17
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-5:
+.. _new-features-6:
 
 New features
 ''''''''''''
@@ -171,7 +243,7 @@ New features
    Jupyter notebooks!
 -  silenced some warnings.
 
-.. _bug-fixes-6:
+.. _bug-fixes-7:
 
 Bug fixes
 '''''''''
@@ -181,6 +253,8 @@ Bug fixes
    now fixed.
 -  fixed a NaN error in confidence intervals for KaplanMeierFitter
 
+.. _api-changes-1:
+
 API Changes
 '''''''''''
 
@@ -191,7 +265,7 @@ API Changes
 -  ``left_censorship`` in ``fit`` has been removed in favour of
    ``fit_left_censoring``.
 
-.. _section-10:
+.. _section-11:
 
 0.22.10 - 2019-11-08
 ^^^^^^^^^^^^^^^^^^^^
@@ -199,7 +273,7 @@ API Changes
 The tests were re-factored to be shipped with the package. Let me know
 if this causes problems.
 
-.. _bug-fixes-7:
+.. _bug-fixes-8:
 
 Bug fixes
 '''''''''
@@ -209,12 +283,12 @@ Bug fixes
 -  fixed bug in plot_covariate_groups for AFT models when >1d arrays
    were used for values arg.
 
-.. _section-11:
+.. _section-12:
 
 0.22.9 - 2019-10-30
 ^^^^^^^^^^^^^^^^^^^
 
-.. _bug-fixes-8:
+.. _bug-fixes-9:
 
 Bug fixes
 '''''''''
@@ -226,12 +300,12 @@ Bug fixes
 -  ``CoxPHFitter`` now displays correct columns values when changing
    alpha param.
 
-.. _section-12:
+.. _section-13:
 
 0.22.8 - 2019-10-06
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-6:
+.. _new-features-7:
 
 New features
 ''''''''''''
@@ -241,19 +315,19 @@ New features
 -  ``conditional_after`` now available in ``CoxPHFitter.predict_median``
 -  Suppressed some unimportant warnings.
 
-.. _bug-fixes-9:
+.. _bug-fixes-10:
 
 Bug fixes
 '''''''''
 
 -  fixed initial_point being ignored in AFT models.
 
-.. _section-13:
+.. _section-14:
 
 0.22.7 - 2019-09-29
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-7:
+.. _new-features-8:
 
 New features
 ''''''''''''
@@ -261,7 +335,7 @@ New features
 -  new ``ApproximationWarning`` to tell you if the package is making an
    potentially mislead approximation.
 
-.. _bug-fixes-10:
+.. _bug-fixes-11:
 
 Bug fixes
 '''''''''
@@ -270,7 +344,7 @@ Bug fixes
 -  realigned values in ``print_summary``.
 -  fixed bug in ``survival_difference_at_fixed_point_in_time_test``
 
-.. _api-changes-1:
+.. _api-changes-2:
 
 API Changes
 '''''''''''
@@ -280,24 +354,24 @@ API Changes
 -  Some previous ``StatisticalWarnings`` have been replaced by
    ``ApproximationWarning``
 
-.. _section-14:
+.. _section-15:
 
 0.22.6 - 2019-09-25
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-8:
+.. _new-features-9:
 
 New features
 ''''''''''''
 
 -  ``conditional_after`` works for ``CoxPHFitter`` prediction models 😅
 
-.. _bug-fixes-11:
+.. _bug-fixes-12:
 
 Bug fixes
 '''''''''
 
-.. _api-changes-2:
+.. _api-changes-3:
 
 API Changes
 '''''''''''
@@ -308,12 +382,12 @@ API Changes
 -  ``utils.dataframe_interpolate_at_times`` renamed to
    ``utils.interpolate_at_times_and_return_pandas``.
 
-.. _section-15:
+.. _section-16:
 
 0.22.5 - 2019-09-20
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-9:
+.. _new-features-10:
 
 New features
 ''''''''''''
@@ -322,7 +396,7 @@ New features
    weights.
 -  Better support for predicting on Pandas Series
 
-.. _bug-fixes-12:
+.. _bug-fixes-13:
 
 Bug fixes
 '''''''''
@@ -331,7 +405,7 @@ Bug fixes
 -  Fixed an issue with ``AalenJohansenFitter`` failing to plot
    confidence intervals.
 
-.. _api-changes-3:
+.. _api-changes-4:
 
 API Changes
 '''''''''''
@@ -339,12 +413,12 @@ API Changes
 -  ``_get_initial_value`` in parametric univariate models is renamed
    ``_create_initial_point``
 
-.. _section-16:
+.. _section-17:
 
 0.22.4 - 2019-09-04
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-10:
+.. _new-features-11:
 
 New features
 ''''''''''''
@@ -355,7 +429,7 @@ New features
 -  new ``utils.restricted_mean_survival_time`` that approximates the
    RMST using numerical integration against survival functions.
 
-.. _api-changes-4:
+.. _api-changes-5:
 
 API changes
 '''''''''''
@@ -363,7 +437,7 @@ API changes
 -  ``KaplanMeierFitter.survival_function_``\ ‘s’ index is no longer
    given the name “timeline”.
 
-.. _bug-fixes-13:
+.. _bug-fixes-14:
 
 Bug fixes
 '''''''''
@@ -371,12 +445,12 @@ Bug fixes
 -  Fixed issue where ``concordance_index`` would never exit if NaNs in
    dataset.
 
-.. _section-17:
+.. _section-18:
 
 0.22.3 - 2019-08-08
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-11:
+.. _new-features-12:
 
 New features
 ''''''''''''
@@ -389,7 +463,7 @@ New features
 -  smarter initial conditions for parametric regression models.
 -  New regression model: ``GeneralizedGammaRegressionFitter``
 
-.. _api-changes-5:
+.. _api-changes-6:
 
 API changes
 '''''''''''
@@ -400,7 +474,7 @@ API changes
    gains only in Cox models, and only a small fraction of the API was
    being used.
 
-.. _bug-fixes-14:
+.. _bug-fixes-15:
 
 Bug fixes
 '''''''''
@@ -412,19 +486,19 @@ Bug fixes
 -  Fixed an error in the ``predict_percentile`` of
    ``LogLogisticAFTFitter``. New tests have been added around this.
 
-.. _section-18:
+.. _section-19:
 
 0.22.2 - 2019-07-25
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-12:
+.. _new-features-13:
 
 New features
 ''''''''''''
 
 -  lifelines is now compatible with scipy>=1.3.0
 
-.. _bug-fixes-15:
+.. _bug-fixes-16:
 
 Bug fixes
 '''''''''
@@ -435,12 +509,12 @@ Bug fixes
    errors when using the library. The correctly numpy has been pinned
    (to 1.14.0+)
 
-.. _section-19:
+.. _section-20:
 
 0.22.1 - 2019-07-14
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-13:
+.. _new-features-14:
 
 New features
 ''''''''''''
@@ -455,7 +529,7 @@ New features
    right censoring)
 -  improvements to ``lifelines.utils.gamma``
 
-.. _api-changes-6:
+.. _api-changes-7:
 
 API changes
 '''''''''''
@@ -468,7 +542,7 @@ API changes
    ``.print_summary`` includes confidence intervals for the exponential
    of the value.
 
-.. _bug-fixes-16:
+.. _bug-fixes-17:
 
 Bug fixes
 '''''''''
@@ -478,12 +552,12 @@ Bug fixes
 -  fixed an overflow bug in ``KaplanMeierFitter`` confidence intervals
 -  improvements in data validation for ``CoxTimeVaryingFitter``
 
-.. _section-20:
+.. _section-21:
 
 0.22.0 - 2019-07-03
-~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-14:
+.. _new-features-15:
 
 New features
 ''''''''''''
@@ -495,7 +569,7 @@ New features
 -  for parametric univariate models, the ``conditional_time_to_event_``
    is now exact instead of an approximation.
 
-.. _api-changes-7:
+.. _api-changes-8:
 
 API changes
 '''''''''''
@@ -517,7 +591,7 @@ API changes
    could set ``fit_intercept`` to False and not have to set
    ``ancillary_df`` - now one must specify a DataFrame.
 
-.. _bug-fixes-17:
+.. _bug-fixes-18:
 
 Bug fixes
 '''''''''
@@ -526,21 +600,21 @@ Bug fixes
    is now exact instead of an approximation.
 -  fixed a name error bug in ``CoxTimeVaryingFitter.plot``
 
-.. _section-21:
+.. _section-22:
 
 0.21.5 - 2019-06-22
 ^^^^^^^^^^^^^^^^^^^
 
 I’m skipping 0.21.4 version because of deployment issues.
 
-.. _new-features-15:
+.. _new-features-16:
 
 New features
 ''''''''''''
 
 -  ``scoring_method`` now a kwarg on ``sklearn_adapter``
 
-.. _bug-fixes-18:
+.. _bug-fixes-19:
 
 Bug fixes
 '''''''''
@@ -550,12 +624,12 @@ Bug fixes
 -  fixed visual bug that misaligned x-axis ticks and at-risk counts.
    Thanks @christopherahern!
 
-.. _section-22:
+.. _section-23:
 
 0.21.3 - 2019-06-04
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-16:
+.. _new-features-17:
 
 New features
 ''''''''''''
@@ -569,19 +643,19 @@ New features
 -  ``CoxPHFitter.check_assumptions`` now accepts a ``columns`` parameter
    to specify only checking a subset of columns.
 
-.. _bug-fixes-19:
+.. _bug-fixes-20:
 
 Bug fixes
 '''''''''
 
 -  ``covariates_from_event_matrix`` handle nulls better
 
-.. _section-23:
+.. _section-24:
 
 0.21.2 - 2019-05-16
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-17:
+.. _new-features-18:
 
 New features
 ''''''''''''
@@ -593,7 +667,7 @@ New features
    that computes, you guessed it, the log-likelihood ratio test.
    Previously this was an internal API that is being exposed.
 
-.. _api-changes-8:
+.. _api-changes-9:
 
 API changes
 '''''''''''
@@ -605,17 +679,17 @@ API changes
 -  removing ``_compute_likelihood_ratio_test`` on regression models. Use
    ``log_likelihood_ratio_test`` now.
 
-.. _bug-fixes-20:
+.. _bug-fixes-21:
 
 Bug fixes
 '''''''''
 
-.. _section-24:
+.. _section-25:
 
 0.21.1 - 2019-04-26
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-18:
+.. _new-features-19:
 
 New features
 ''''''''''''
@@ -624,7 +698,7 @@ New features
    ``add_covariate_to_timeline``
 -  PiecewiseExponentialFitter now allows numpy arrays as breakpoints
 
-.. _api-changes-9:
+.. _api-changes-10:
 
 API changes
 '''''''''''
@@ -632,19 +706,19 @@ API changes
 -  output of ``survival_table_from_events`` when collapsing rows to
    intervals now removes the “aggregate” column multi-index.
 
-.. _bug-fixes-21:
+.. _bug-fixes-22:
 
 Bug fixes
 '''''''''
 
 -  fixed bug in CoxTimeVaryingFitter when ax is provided, thanks @j-i-l!
 
-.. _section-25:
+.. _section-26:
 
 0.21.0 - 2019-04-12
-~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-19:
+.. _new-features-20:
 
 New features
 ''''''''''''
@@ -658,7 +732,7 @@ New features
 -  a new interval censored dataset is available under
    ``lifelines.datasets.load_diabetes``
 
-.. _api-changes-10:
+.. _api-changes-11:
 
 API changes
 '''''''''''
@@ -669,7 +743,7 @@ API changes
 -  ``entries`` property in multivariate parametric models has a new
    Series name: ``entry``
 
-.. _bug-fixes-22:
+.. _bug-fixes-23:
 
 Bug fixes
 '''''''''
@@ -679,19 +753,19 @@ Bug fixes
 -  Fixed an error that didn’t let users use Numpy arrays in prediction
    for AFT models
 
-.. _section-26:
+.. _section-27:
 
 0.20.5 - 2019-04-08
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-20:
+.. _new-features-21:
 
 New features
 ''''''''''''
 
 -  performance improvements for ``print_summary``.
 
-.. _api-changes-11:
+.. _api-changes-12:
 
 API changes
 '''''''''''
@@ -701,7 +775,7 @@ API changes
 -  in ``AalenJohansenFitter``, the ``variance`` parameter is renamed to
    ``variance_`` to align with the usual lifelines convention.
 
-.. _bug-fixes-23:
+.. _bug-fixes-24:
 
 Bug fixes
 '''''''''
@@ -710,12 +784,12 @@ Bug fixes
    test when using strata.
 -  Fixed some plotting bugs with ``AalenJohansenFitter``
 
-.. _section-27:
+.. _section-28:
 
 0.20.4 - 2019-03-27
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-21:
+.. _new-features-22:
 
 New features
 ''''''''''''
@@ -726,7 +800,7 @@ New features
    generating piecewise exp. data
 -  Faster ``print_summary`` for AFT models.
 
-.. _api-changes-12:
+.. _api-changes-13:
 
 API changes
 '''''''''''
@@ -734,7 +808,7 @@ API changes
 -  Pandas is now correctly pinned to >= 0.23.0. This was always the
    case, but not specified in setup.py correctly.
 
-.. _bug-fixes-24:
+.. _bug-fixes-25:
 
 Bug fixes
 '''''''''
@@ -743,12 +817,12 @@ Bug fixes
 -  ``PiecewiseExponentialFitter`` is available with
    ``from lifelines import *``.
 
-.. _section-28:
+.. _section-29:
 
 0.20.3 - 2019-03-23
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-22:
+.. _new-features-23:
 
 New features
 ''''''''''''
@@ -761,12 +835,12 @@ New features
    ``plot_survival_function`` and
    ``confidence_interval_survival_function_``.
 
-.. _section-29:
+.. _section-30:
 
 0.20.2 - 2019-03-21
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-23:
+.. _new-features-24:
 
 New features
 ''''''''''''
@@ -781,7 +855,7 @@ New features
 -  add a ``lifelines.plotting.qq_plot`` for univariate parametric models
    that handles censored data.
 
-.. _api-changes-13:
+.. _api-changes-14:
 
 API changes
 '''''''''''
@@ -790,7 +864,7 @@ API changes
    @vpolimenov!
 -  The ``C`` column in ``load_lcd`` dataset is renamed to ``E``.
 
-.. _bug-fixes-25:
+.. _bug-fixes-26:
 
 Bug fixes
 '''''''''
@@ -806,7 +880,7 @@ Bug fixes
    the q parameter was below the truncation limit. This should have been
    ``-np.inf``
 
-.. _section-30:
+.. _section-31:
 
 0.20.1 - 2019-03-16
 ^^^^^^^^^^^^^^^^^^^
@@ -820,7 +894,7 @@ Bug fixes
    decades of development.
 -  suppressed unimportant warnings
 
-.. _api-changes-14:
+.. _api-changes-15:
 
 API changes
 '''''''''''
@@ -830,16 +904,16 @@ API changes
    This is no longer the case. A 0 will still be added if there is a
    duration (observed or not) at 0 occurs however.
 
-.. _section-31:
+.. _section-32:
 
 0.20.0 - 2019-03-05
-~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^
 
 -  Starting with 0.20.0, only Python3 will be supported. Over 75% of
    recent installs where Py3.
 -  Updated minimum dependencies, specifically Matplotlib and Pandas.
 
-.. _new-features-24:
+.. _new-features-25:
 
 New features
 ''''''''''''
@@ -847,7 +921,7 @@ New features
 -  smarter initialization for AFT models which should improve
    convergence.
 
-.. _api-changes-15:
+.. _api-changes-16:
 
 API changes
 '''''''''''
@@ -859,19 +933,19 @@ API changes
    transposed now (previous parameters where columns, now parameters are
    rows).
 
-.. _bug-fixes-26:
+.. _bug-fixes-27:
 
 Bug fixes
 '''''''''
 
 -  Fixed a bug with plotting and ``check_assumptions``.
 
-.. _section-32:
+.. _section-33:
 
 0.19.5 - 2019-02-26
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-25:
+.. _new-features-26:
 
 New features
 ''''''''''''
@@ -881,24 +955,24 @@ New features
    features or categorical variables.
 -  Convergence improvements for AFT models.
 
-.. _section-33:
+.. _section-34:
 
 0.19.4 - 2019-02-25
 ^^^^^^^^^^^^^^^^^^^
 
-.. _bug-fixes-27:
+.. _bug-fixes-28:
 
 Bug fixes
 '''''''''
 
 -  remove some bad print statements in ``CoxPHFitter``.
 
-.. _section-34:
+.. _section-35:
 
 0.19.3 - 2019-02-25
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-26:
+.. _new-features-27:
 
 New features
 ''''''''''''
@@ -910,12 +984,12 @@ New features
 -  Performance increase to ``print_summary`` in the ``CoxPHFitter`` and
    ``CoxTimeVaryingFitter`` model.
 
-.. _section-35:
+.. _section-36:
 
 0.19.2 - 2019-02-22
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-27:
+.. _new-features-28:
 
 New features
 ''''''''''''
@@ -923,7 +997,7 @@ New features
 -  ``ParametricUnivariateFitters``, like ``WeibullFitter``, have
    smoothed plots when plotting (vs stepped plots)
 
-.. _bug-fixes-28:
+.. _bug-fixes-29:
 
 Bug fixes
 '''''''''
@@ -933,12 +1007,12 @@ Bug fixes
 -  Univariate fitters are more flexiable and can allow 2-d and
    DataFrames as inputs.
 
-.. _section-36:
+.. _section-37:
 
 0.19.1 - 2019-02-21
 ^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-28:
+.. _new-features-29:
 
 New features
 ''''''''''''
@@ -946,7 +1020,7 @@ New features
 -  improved stability of ``LogNormalFitter``
 -  Matplotlib for Python3 users are not longer forced to use 2.x.
 
-.. _api-changes-16:
+.. _api-changes-17:
 
 API changes
 '''''''''''
@@ -955,12 +1029,12 @@ API changes
    ``PiecewiseExponential`` to the same as ``ExponentialFitter`` (from
    ``\lambda * t`` to ``t / \lambda``).
 
-.. _section-37:
+.. _section-38:
 
 0.19.0 - 2019-02-20
-~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^
 
-.. _new-features-29:
+.. _new-features-30:
 
 New features
 ''''''''''''
@@ -973,7 +1047,7 @@ New features
 -  ``CoxPHFitter`` performance improvements (about 10%)
 -  ``CoxTimeVaryingFitter`` performance improvements (about 10%)
 
-.. _api-changes-17:
+.. _api-changes-18:
 
 API changes
 '''''''''''
@@ -999,7 +1073,7 @@ API changes
    means that the *default* for alpha is set to 0.05 in the latest
    lifelines, instead of 0.95 in previous versions.
 
-.. _bug-fixes-29:
+.. _bug-fixes-30:
 
 Bug Fixes
 '''''''''
@@ -1016,7 +1090,7 @@ Bug Fixes
    models. Thanks @airanmehr!
 -  Fixed some Pandas <0.24 bugs.
 
-.. _section-38:
+.. _section-39:
 
 0.18.6 - 2019-02-13
 ^^^^^^^^^^^^^^^^^^^
@@ -1026,7 +1100,7 @@ Bug Fixes
    ``rank`` and ``km`` p-values now.
 -  some performance improvements to ``qth_survival_time``.
 
-.. _section-39:
+.. _section-40:
 
 0.18.5 - 2019-02-11
 ^^^^^^^^^^^^^^^^^^^
@@ -1047,7 +1121,7 @@ Bug Fixes
    that can be used to turn off variance calculations since this can
    take a long time for large datasets. Thanks @pzivich!
 
-.. _section-40:
+.. _section-41:
 
 0.18.4 - 2019-02-10
 ^^^^^^^^^^^^^^^^^^^
@@ -1057,7 +1131,7 @@ Bug Fixes
 -  adding left-truncation support to parametric univarite models with
    the ``entry`` kwarg in ``.fit``
 
-.. _section-41:
+.. _section-42:
 
 0.18.3 - 2019-02-07
 ^^^^^^^^^^^^^^^^^^^
@@ -1067,7 +1141,7 @@ Bug Fixes
    warnings are more noticeable.
 -  Improved some warning and error messages.
 
-.. _section-42:
+.. _section-43:
 
 0.18.2 - 2019-02-05
 ^^^^^^^^^^^^^^^^^^^
@@ -1083,7 +1157,7 @@ Bug Fixes
    Moved them all (most) to use ``autograd``.
 -  ``LogNormalFitter`` no longer models ``log_sigma``.
 
-.. _section-43:
+.. _section-44:
 
 0.18.1 - 2019-02-02
 ^^^^^^^^^^^^^^^^^^^
@@ -1094,10 +1168,10 @@ Bug Fixes
 -  use the ``autograd`` lib to help with gradients.
 -  New ``LogLogisticFitter`` univariate fitter available.
 
-.. _section-44:
+.. _section-45:
 
 0.18.0 - 2019-01-31
-~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^
 
 -  ``LogNormalFitter`` is a new univariate fitter you can use.
 -  ``WeibullFitter`` now correctly returns the confidence intervals
@@ -1131,7 +1205,7 @@ Bug Fixes
    ``LinAlgError: Matrix is singular.`` and report back to the user
    advice.
 
-.. _section-45:
+.. _section-46:
 
 0.17.5 - 2019-01-25
 ^^^^^^^^^^^^^^^^^^^
@@ -1139,7 +1213,7 @@ Bug Fixes
 -  more bugs in ``plot_covariate_groups`` fixed when using non-numeric
    strata.
 
-.. _section-46:
+.. _section-47:
 
 0.17.4 -2019-01-25
 ^^^^^^^^^^^^^^^^^^
@@ -1151,7 +1225,7 @@ Bug Fixes
 -  ``groups`` is now called ``values`` in
    ``CoxPHFitter.plot_covariate_groups``
 
-.. _section-47:
+.. _section-48:
 
 0.17.3 - 2019-01-24
 ^^^^^^^^^^^^^^^^^^^
@@ -1159,7 +1233,7 @@ Bug Fixes
 -  Fix in ``compute_residuals`` when using ``schoenfeld`` and the
    minumum duration has only censored subjects.
 
-.. _section-48:
+.. _section-49:
 
 0.17.2 2019-01-22
 ^^^^^^^^^^^^^^^^^
@@ -1170,7 +1244,7 @@ Bug Fixes
    ``for`` loop. The downside is the code is more esoteric now. I’ve
    added comments as necessary though 🤞
 
-.. _section-49:
+.. _section-50:
 
 0.17.1 - 2019-01-20
 ^^^^^^^^^^^^^^^^^^^
@@ -1187,10 +1261,10 @@ Bug Fixes
 -  Fixes a Pandas performance warning in ``CoxTimeVaryingFitter``.
 -  Performances improvements to ``CoxTimeVaryingFitter``.
 
-.. _section-50:
+.. _section-51:
 
 0.17.0 - 2019-01-11
-~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^
 
 -  corrected behaviour in ``CoxPHFitter`` where ``score_`` was not being
    refreshed on every new ``fit``.
@@ -1208,7 +1282,7 @@ Bug Fixes
 
 -  some plotting improvemnts to ``plotting.plot_lifetimes``
 
-.. _section-51:
+.. _section-52:
 
 0.16.3 - 2019-01-03
 ^^^^^^^^^^^^^^^^^^^
@@ -1216,7 +1290,7 @@ Bug Fixes
 -  More ``CoxPHFitter`` performance improvements. Up to a 40% reduction
    vs 0.16.2 for some datasets.
 
-.. _section-52:
+.. _section-53:
 
 0.16.2 - 2019-01-02
 ^^^^^^^^^^^^^^^^^^^
@@ -1227,17 +1301,17 @@ Bug Fixes
    has lots of duplicate times. See
    https://github.com/CamDavidsonPilon/lifelines/issues/591
 
-.. _section-53:
+.. _section-54:
 
 0.16.1 - 2019-01-01
 ^^^^^^^^^^^^^^^^^^^
 
 -  Fixed py2 division error in ``concordance`` method.
 
-.. _section-54:
+.. _section-55:
 
 0.16.0 - 2019-01-01
-~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^
 
 -  Drop Python 3.4 support.
 -  introduction of residual calculations in
@@ -1270,7 +1344,7 @@ Bug Fixes
    ``lifelines.utils.to_episodic_format``.
 -  ``CoxTimeVaryingFitter`` now accepts ``strata``.
 
-.. _section-55:
+.. _section-56:
 
 0.15.4
 ^^^^^^
@@ -1278,14 +1352,14 @@ Bug Fixes
 -  bug fix for the Cox model likelihood ratio test when using
    non-trivial weights.
 
-.. _section-56:
+.. _section-57:
 
 0.15.3 - 2018-12-18
 ^^^^^^^^^^^^^^^^^^^
 
 -  Only allow matplotlib less than 3.0.
 
-.. _section-57:
+.. _section-58:
 
 0.15.2 - 2018-11-23
 ^^^^^^^^^^^^^^^^^^^
@@ -1296,7 +1370,7 @@ Bug Fixes
 -  removed ``entry`` from ``ExponentialFitter`` and ``WeibullFitter`` as
    it was doing nothing.
 
-.. _section-58:
+.. _section-59:
 
 0.15.1 - 2018-11-23
 ^^^^^^^^^^^^^^^^^^^
@@ -1305,10 +1379,10 @@ Bug Fixes
 -  Raise NotImplementedError if the ``robust`` flag is used in
    ``CoxTimeVaryingFitter`` - that’s not ready yet.
 
-.. _section-59:
+.. _section-60:
 
 0.15.0 - 2018-11-22
-~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^
 
 -  adding ``robust`` params to ``CoxPHFitter``\ ’s ``fit``. This enables
    atleast i) using non-integer weights in the model (these could be
@@ -1376,7 +1450,7 @@ Bug Fixes
    When Estimating Risks in Pharmacoepidemiology” for a nice overview of
    the model.
 
-.. _section-60:
+.. _section-61:
 
 0.14.6 - 2018-07-02
 ^^^^^^^^^^^^^^^^^^^
@@ -1384,7 +1458,7 @@ Bug Fixes
 -  fix for n > 2 groups in ``multivariate_logrank_test`` (again).
 -  fix bug for when ``event_observed`` column was not boolean.
 
-.. _section-61:
+.. _section-62:
 
 0.14.5 - 2018-06-29
 ^^^^^^^^^^^^^^^^^^^
@@ -1392,7 +1466,7 @@ Bug Fixes
 -  fix for n > 2 groups in ``multivariate_logrank_test``
 -  fix weights in KaplanMeierFitter when using a pandas Series.
 
-.. _section-62:
+.. _section-63:
 
 0.14.4 - 2018-06-14
 ^^^^^^^^^^^^^^^^^^^
@@ -1409,7 +1483,7 @@ Bug Fixes
 -  New ``delay`` parameter in ``add_covariate_to_timeline``
 -  removed ``two_sided_z_test`` from ``statistics``
 
-.. _section-63:
+.. _section-64:
 
 0.14.3 - 2018-05-24
 ^^^^^^^^^^^^^^^^^^^
@@ -1421,7 +1495,7 @@ Bug Fixes
 -  adds a ``column`` argument to ``CoxTimeVaryingFitter`` and
    ``CoxPHFitter`` ``plot`` method to plot only a subset of columns.
 
-.. _section-64:
+.. _section-65:
 
 0.14.2 - 2018-05-18
 ^^^^^^^^^^^^^^^^^^^
@@ -1429,7 +1503,7 @@ Bug Fixes
 -  some quality of life improvements for working with
    ``CoxTimeVaryingFitter`` including new ``predict_`` methods.
 
-.. _section-65:
+.. _section-66:
 
 0.14.1 - 2018-04-01
 ^^^^^^^^^^^^^^^^^^^
@@ -1447,10 +1521,10 @@ Bug Fixes
    faster completion of ``fit`` for large dataframes, and up to 10%
    faster for small dataframes.
 
-.. _section-66:
+.. _section-67:
 
 0.14.0 - 2018-03-03
-~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^
 
 -  adding ``plot_covariate_groups`` to ``CoxPHFitter`` to visualize what
    happens to survival as we vary a covariate, all else being equal.
@@ -1469,10 +1543,10 @@ Bug Fixes
    of a ``RuntimeWarning``
 -  New checks for complete separation in the dataset for regressions.
 
-.. _section-67:
+.. _section-68:
 
 0.13.0 - 2017-12-22
-~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^
 
 -  removes ``is_significant`` and ``test_result`` from
    ``StatisticalResult``. Users can instead choose their significance
@@ -1498,10 +1572,10 @@ Bug Fixes
    group the same subjects together and give that observation a weight
    equal to the count. Altogether, this means a much faster regression.
 
-.. _section-68:
+.. _section-69:
 
 0.12.0
-~~~~~~
+^^^^^^
 
 -  removes ``include_likelihood`` from ``CoxPHFitter.fit`` - it was not
    slowing things down much (empirically), and often I wanted it for
@@ -1515,7 +1589,7 @@ Bug Fixes
 -  Additional functionality to ``utils.survival_table_from_events`` to
    bin the index to make the resulting table more readable.
 
-.. _section-69:
+.. _section-70:
 
 0.11.3
 ^^^^^^
@@ -1527,7 +1601,7 @@ Bug Fixes
    observation or censorship.
 -  More accurate prediction methods parametrics univariate models.
 
-.. _section-70:
+.. _section-71:
 
 0.11.2
 ^^^^^^
@@ -1535,17 +1609,17 @@ Bug Fixes
 -  Changing liscense to valilla MIT.
 -  Speed up ``NelsonAalenFitter.fit`` considerably.
 
-.. _section-71:
+.. _section-72:
 
 0.11.1 - 2017-06-22
 ^^^^^^^^^^^^^^^^^^^
 
 -  Python3 fix for ``CoxPHFitter.plot``.
 
-.. _section-72:
+.. _section-73:
 
 0.11.0 - 2017-06-21
-~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^
 
 -  fixes regression in ``KaplanMeierFitter.plot`` when using Seaborn and
    lifelines.
@@ -1556,17 +1630,17 @@ Bug Fixes
    of a new ``loc`` kwarg. This is to align with Pandas deprecating
    ``ix``
 
-.. _section-73:
+.. _section-74:
 
 0.10.1 - 2017-06-05
 ^^^^^^^^^^^^^^^^^^^
 
 -  fix in internal normalization for ``CoxPHFitter`` predict methods.
 
-.. _section-74:
+.. _section-75:
 
 0.10.0
-~~~~~~
+^^^^^^
 
 -  corrected bug that was returning the wrong baseline survival and
    hazard values in ``CoxPHFitter`` when ``normalize=True``.
@@ -1578,7 +1652,7 @@ Bug Fixes
    mimic R’s ``basehaz`` API.
 -  new ``predict_log_partial_hazards`` to ``CoxPHFitter``
 
-.. _section-75:
+.. _section-76:
 
 0.9.4
 ^^^^^
@@ -1601,7 +1675,7 @@ Bug Fixes
 -  performance improvements in ``CoxPHFitter`` - should see at least a
    10% speed improvement in ``fit``.
 
-.. _section-76:
+.. _section-77:
 
 0.9.2
 ^^^^^
@@ -1610,7 +1684,7 @@ Bug Fixes
 -  throw an error if no admissable pairs in the c-index calculation.
    Previously a NaN was returned.
 
-.. _section-77:
+.. _section-78:
 
 0.9.1
 ^^^^^
@@ -1618,10 +1692,10 @@ Bug Fixes
 -  add two summary functions to Weibull and Exponential fitter, solves
    #224
 
-.. _section-78:
+.. _section-79:
 
 0.9.0
-~~~~~
+^^^^^
 
 -  new prediction function in ``CoxPHFitter``,
    ``predict_log_hazard_relative_to_mean``, that mimics what R’s
@@ -1634,7 +1708,7 @@ Bug Fixes
 -  Default predict method in ``k_fold_cross_validation`` is now
    ``predict_expectation``
 
-.. _section-79:
+.. _section-80:
 
 0.8.1 - 2015-08-01
 ^^^^^^^^^^^^^^^^^^
@@ -1651,10 +1725,10 @@ Bug Fixes
    -  scaling of smooth hazards in NelsonAalenFitter was off by a factor
       of 0.5.
 
-.. _section-80:
+.. _section-81:
 
 0.8.0
-~~~~~
+^^^^^
 
 -  reorganized lifelines directories:
 
@@ -1670,7 +1744,7 @@ Bug Fixes
    ``lifelines.statistics. power_under_cph``.
 -  fixed a bug when using KaplanMeierFitter for left-censored data.
 
-.. _section-81:
+.. _section-82:
 
 0.7.1
 ^^^^^
@@ -1689,10 +1763,10 @@ Bug Fixes
 -  refactor each fitter into it’s own submodule. For now, the tests are
    still in the same file. This will also *not* break the API.
 
-.. _section-82:
+.. _section-83:
 
 0.7.0 - 2015-03-01
-~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^
 
 -  allow for multiple fitters to be passed into
    ``k_fold_cross_validation``.
@@ -1708,7 +1782,7 @@ Bug Fixes
    duration remaining until the death event, given survival up until
    time t.
 
-.. _section-83:
+.. _section-84:
 
 0.6.1
 ^^^^^
@@ -1720,10 +1794,10 @@ Bug Fixes
    your work is to sum up the survival function (for expected values or
    something similar), it’s more difficult to make a mistake.
 
-.. _section-84:
+.. _section-85:
 
 0.6.0 - 2015-02-04
-~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^
 
 -  Inclusion of the univariate fitters ``WeibullFitter`` and
    ``ExponentialFitter``.
@@ -1743,7 +1817,7 @@ Bug Fixes
 -  In ``KaplanMeierFitter``, ``epsilon`` has been renamed to
    ``precision``.
 
-.. _section-85:
+.. _section-86:
 
 0.5.1 - 2014-12-24
 ^^^^^^^^^^^^^^^^^^
@@ -1764,10 +1838,10 @@ Bug Fixes
    ``lifelines.plotting.add_at_risk_counts``.
 -  Fix bug Epanechnikov kernel.
 
-.. _section-86:
+.. _section-87:
 
 0.5.0 - 2014-12-07
-~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^
 
 -  move testing to py.test
 -  refactor tests into smaller files
@@ -1777,7 +1851,7 @@ Bug Fixes
 -  add test for summary()
 -  Alternate metrics can be used for ``k_fold_cross_validation``.
 
-.. _section-87:
+.. _section-88:
 
 0.4.4 - 2014-11-27
 ^^^^^^^^^^^^^^^^^^
@@ -1789,7 +1863,7 @@ Bug Fixes
 -  Fixes bug in 1-d input not returning in CoxPHFitter
 -  Lots of new tests.
 
-.. _section-88:
+.. _section-89:
 
 0.4.3 - 2014-07-23
 ^^^^^^^^^^^^^^^^^^
@@ -1810,7 +1884,7 @@ Bug Fixes
 -  Adds option ``include_likelihood`` to CoxPHFitter fit method to save
    the final log-likelihood value.
 
-.. _section-89:
+.. _section-90:
 
 0.4.2 - 2014-06-19
 ^^^^^^^^^^^^^^^^^^
@@ -1830,12 +1904,12 @@ Bug Fixes
    from failing so often (this a stop-gap)
 -  pep8 everything
 
-.. _section-90:
+.. _section-91:
 
 0.4.1.1
 ^^^^^^^
 
--  Ability to specify default printing in statsitical tests with the
+-  Ability to specify default printing in statistical tests with the
    ``suppress_print`` keyword argument (default False).
 -  For the multivariate log rank test, the inverse step has been
    replaced with the generalized inverse. This seems to be what other
@@ -1843,7 +1917,7 @@ Bug Fixes
 -  Adding more robust cross validation scheme based on issue #67.
 -  fixing ``regression_dataset`` in ``datasets``.
 
-.. _section-91:
+.. _section-92:
 
 0.4.1 - 2014-06-11
 ^^^^^^^^^^^^^^^^^^
@@ -1862,10 +1936,10 @@ Bug Fixes
 -  Adding a Changelog.
 -  more sanitizing for the statistical tests =)
 
-.. _section-92:
+.. _section-93:
 
 0.4.0 - 2014-06-08
-~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^
 
 -  ``CoxFitter`` implements Cox Proportional Hazards model in lifelines.
 -  lifelines moves the wheels distributions.