My team is trying to decide which is best practice. We currently have a test where we have a Control that does nothing on the page (Default Content), and a Challenger where if the visitor lands on the control page, they get redirected (via Target Redirect Offer) to another page (let's call this page B). For setting up the test and for visitor count to be accurate for the test, should we also include the mbox for page B for this test (and keep the offer as Default Content)?
One argument (for if we include page B mbox in the campaign) is that if the visitor copies the redirected URL and uses another browser, they will be counted as another visitor.
Another argument (for if we do not include page B mbox in the campaign), is that if the visitor copies the redirected URL and uses another browser, they will not be counted in the campaign conversion.
Which one is correct? Also, do we need to do the same for Standard? We have an mbox that is common on all our pages, and Page B location would be added by page URL.
Another use case to consider is what happens if a visitor shares either link with a friend.
Because of the nature of cookies, you will always will have some cross-recipe contamination. Unless you authenticate, its unachievable goal to remove it. You can try to balance it so the effects hit both recipes equally.
Redirects usually have a negative effect on performance and depending on your experiment configuration it could be significant by itself, putting page B at a slight disadvantage.
Redirects can happen before the Analytics fires and your landing page will be page B (true) with the source (e.g. referrer) as page A (not true). You may want to add code to handle source data like browser referrer and campaign IDs by passing it in the querystring or a cookie.
Anyway, I would suggest setting something like this:
Page A with no ‘r’ querystring: Redirect to itself adding ‘r=y’ and source info to the querystring
Page B: Redirect to page A adding ‘r=y’ and source info to the querystring
Page A: Redirect to page B adding ‘r=y’ and source info to the querystring
Page B with no ‘r’ querystring: Redirect to itself adding r=y and source info to the querystring
I’m not sure you really need to add querystrings to the 'A' to/from 'B' offers, it just makes me feel better that all the offers act about the same.