.. _fwflag_prefix_super_groups:
========================
--prefix_super_groups
========================
Switch
======

--prefix_super_groups

Description
===========

When stratifying cross-validation folds with :doc:`fwflag_stratify_folds`, treats a prefix of each group id as a "super group" to stratify by, instead of the full group id.

Argument and Default Value
==========================

No argument. Boolean switch, default: ``False``.

Details
=======

Passed as ``stratifyPrefixSuperGroups`` into ``RegressionPredictor.testControlCombos()``. Useful when group ids are structured (e.g. a county FIPS code where the first few digits are a state), so folds are balanced across the higher-level grouping rather than the raw id.

Other Switches
==============

Required Switches:

* :doc:`fwflag_combo_test_regression`
* :doc:`fwflag_stratify_folds`

Example Commands
================

Using the packaged ``dla_tutorial`` dataset (see :doc:`../../tutorials/tut_dla`):

.. code-block:: bash

	dlatkInterface.py -d dla_tutorial -t msgs -c user_id -f 'feat$1to3gram$msgs$user_id$0_05' \
	--outcome_table blog_outcomes --outcomes age --combo_test_regression \
	--stratify_folds --prefix_super_groups