

Architecture update: leaner, meaner and faster A/B tests - paraschopra
http://visualwebsiteoptimizer.com/split-testing-blog/architecture-update-leaner-meaner-and-faster-ab-tests/

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btilly
_Until now you could run only one test per page. While this is the way it
should actually be..._

Um, no.

A/B testing is a balancing act between theory and pragmatism. Everyone wants
to get the perfect answer, but we need to get it fast enough to make useful
business decisions. When your website doesn't have that much traffic this
means you need to make compromises. Running multiple tests at a time on a page
is such a compromise.

The one time you absolutely cannot justify multiple tests at the same time due
to predictable interaction effects is when you've assigned users a sequence
and use the sequence number mod n to figure out which version they get. That's
bad, so don't do that. Even if the tests are on different pages you'll get
interaction effects. Assign people to each test randomly instead.

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paraschopra
To clarify, I meant that you coudln't run multiple tests per page _using_ VWO.
Of course, it has been done previously.

Yes, running multiple tests is risky and we discourage it because even if you
gain speed, the interaction effects may dissolve any results you get.

Again, your last point is excellent. Assigning user ids and then choosing
variations dependent on it is a poor strategy. In VWO, we assign variations
randomly and then remember (via a cookie) which variation did the user see.

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patio11
_Yes, running multiple tests is risky and we discourage it because even if you
gain speed, the interaction effects may dissolve any results you get._

Ben has IIRC previously written, and I agree, that interaction effects are
typically minimal in practice _unless_ you have catastrophic implementation
choices. Since you're taking care of the implementation and it isn't
catastrophic, you can safely ignore them. Don't advise your users against
using your software in a manner likely to increase the value they get out of
it. Interaction effects are worth an asterix in the documentation, but not
much more.

~~~
paraschopra
Yes, you are probably true. But I have seen users permanently implementing a
variation on the slightest hint of improvement, so it is better to take a
strict stance because they are going to ignore it anyway.

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nopassrecover
This is the second time today I've seen a service using one of the admin panel
templates from ThemeForest. In any case it's not the interface that matters so
much in this case.

~~~
paraschopra
Yep, admin interface from ThemeForest provide a really good looking base for
apps such as VWO to build their UI. I love ThemeForest and highly recommend it
for all kinds of design needs.

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danskil
I like the service and just applied for an invite. The demo on the main page
shows changing text can you also change css, swap images, or use different
html elements?

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paraschopra
Yes, see this post for details [http://visualwebsiteoptimizer.com/split-
testing-blog/web-des...](http://visualwebsiteoptimizer.com/split-testing-
blog/web-designers-and-developers-we-have-changed-ab-testing-forever/)

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briancray
I've been using VWO, and highly recommend it.

