End User Interaction
====================
Normandy has a few ways that end-users of Firefox can interact with it.

about:studies
-------------
.. image:: about_studies.png
   :align: center

Users can view active and complete experiments they've participated in on
``about:studies``. They can also manually end an active study using the
Remove buttons on this page. This includes both preference experiments and
add-on experiments (opt-out-studies).

The top of the page links to a SUMO article explaining studies, as well as to
the `opt-out preference`_.

.. _opt-out preference:

Opt-Out Preference
------------------
.. image:: opt_out_pref.png
   :align: center

Normandy adds a preference to ``about:preferences`` under the Privacy &
Security tab, labeled "Allow Firefox to install and run studies" that
defaults to being checked and links to ``about:studies``. It controls the
``app.shield.optoutstudies.enabled`` preference in ``about:config``.

If unchecked, the user will not be enrolled in any new studies.

The checkbox is linked to the one above it: "Allow Nightly to automatically
send technical and interaction data to Mozilla". If that preference is
unchecked, the opt-out preference will also be unchecked and disabled until
the user checks the data one again (at which point the opt-out preference
becomes checked once more).

Ending a Study
--------------
The following events can cause a study to end before the add-on uninstalls
itself:

* The user uninstalls the add-on manually, or while Firefox is closed.
* The recipe for the study is disabled; the study will end the next time the
  user fetches recipes.