== Test principles ==
**We will include all contributors in the A/B test who:**
- Do not have a sticky preference set
- Have made <100 overall edits
- Are anonymous or registered users
**Bucketing criteria**
The first time we see an anonymous user, we should use client-side logic to randomize them into either bucket and then set a cookie so that every EditAttemptStep event sent from them includes the appropriate value in the [“bucket” field](https://meta.wikimedia.org/wiki/Schema:EditAttemptStep). If we’re doing this for anonymous editors, we should do it the same way for registered users as well.
**Storing persistent identifiers for bucketed anons**
We have to run test and conduct analysis within 90 days of test start date. We could use IP address + user agent as the ID, or create and store our own (more robust but harder and probably not worth the effort).
###Research questions*
//Does VE being the default mobile editing interface...//
- Increase edit completion rate?
- Increase the number of successful edits contributor make over a tbd period of time?
- Increase editor retention?
- Increase the number of switched-editor-type actions? (I.e. people fleeing back to wikitext.)
*See T221187
###Blocking questions
- [ ] Is legal okay with us creating a persistent identifier for anonymous contributors (doing this this would anonymous contributors less anonymous?
- [ ] Whether we decide to store a persistent identifier based on IP + user agent or create and store our own requires a modification to [EditAttemptStep](https://meta.wikimedia.org/wiki/Schema:EditAttemptStep): how should changes to EditAttemptStep be implemented?
###Open questions
- [x] Under what conditions are contributors' editing interface preferences set? See T221195#5201746
- [x] How will we bucket users if we want to include contributors who are not logged in?
- [ ] What level of precision is appropriate for this A/B test?
- [x] What wikis are being included in this A/B test? See T222803
- [x] Confirm: we can distinguish between contributors who do and do not have a sticky editing interface preference set? **Yes**
- [ ] Confirm: what impact – in terms of scale – does including all contributors who do not have a sticky preference set on the number of edit sessions
- [ ] How long will the test last?
- [ ] How are we going to monitor the test? What will trigger us to interrupt the test?
- [ ] What are the range of actions we could take after the test concludes? What will determine which action(s) we take?
- [ ] What could we do to exclude editors from our edit completion rate numbers who we assume do not have any intention of completing an actual edit?
###"Done"
- [ ] A phabricator task is created that specifies how engineering should implement/instrument the A/B test