I created a Subject Line A/B test for a Smart Campaign. Where can I view which subject line won?

Hi Geoffrey, did you set up a champion/challenger test on a batch campaign or on a triggered campaign? If you set the champion/challenger test on a triggered campaign, then you should be able to see results by going to the A/B test dashboard. If you ran a batch campaign, then you're probably seeing results that look like only one of the emails sent, which is exactly what happened. Unfortunately, champion/challenger doesn't work on batch campaigns -- only triggered campaigns.

If you set this up under a single-send email program, then you should be able to change the view to "Dashboard", and see the results.

Thanks for the prompt reply! So... does this mean I can't do A/B tests on Smart Campaigns? 

It depends on how you set it up. I've been doing one of three things... you can do a the champion/challenger tests by adding everyone to a list and then having a triggered campaign once they're added to the list. Champion/challengers still aren't the ideal for me because once you declare a champion, the results of the test are no longer available. You could also do an email program, it's just not my preferred method of sending.

My preferred method of setting up a "test" would be to create two separate emails, create my send campaign, and in the flow step I choose send email but then I add a choice, if random sample = 50% (or other percentage) send email 1, otherwise send email 2. It's a little bit more work to create the second email, but otherwise I find it to be the most convenient way to send a split email to 100% of my audience at the same time.