Friday, 11 July 2014

Is Multi-Variate Testing Really That Good?

The second discussion that I led at the Digital Analytics Hub in Berlin in June was entitled, "Is Multi Variate Testing Really That Good?"  Although only a few delegates attended, it got some good participation from a range of people representing a range of analytical and digital professionals, and in this post I'll cover some of the key points.

- The number of companies using MVT is starting to increase, although it's a very slow increase and it still has only low adoption rates. It's not as widespread as perhaps the tool vendors would suggest.

- The main barriers (real or perceived) to MVT are complexity (in design and analysis) and traffic volumes (multiple recipes require large volumes of traffic in order to get meaningful results in a useful timeframe).

There is an inherent level of complexity in MVT, as I've mentioned before (and one day soon I will explain how to analyse the results) and the tool vendors seem to imply that the test design must also be complicated.  It doesn't.  I've mentioned in a previous post on MVT that sometimes the visual design of a multi-variate test does not have to be complicated, it can just involve a large number of small changes run simultaneously.   

The general view during the discussion was that MVT would have to involve a complicated design with a large number of variations per element (e.g. testing a call-to-action button in red, green, yellow, orange and blue, with five different wordings).  In my opinion, this would be complicated as an A/B/n test, so as an MVT it would be extremely complex, and, to be honest, totally unsuitable for an entry-level test.

We spent a lot of our discussion time discussing various pages and scenarios where MVT is totally unsuitable, such as site navigation.  A number of online sites have issues with large catalogues and navigation hierarchies, and it's difficult to decide how best to display the whole range of products - MVT isn't the tool to use here, we discussed card-sorting, brainstorming and visualisations instead of A/B testing.  This was one of the key lessons for me - MVT is a powerful tool, but sometimes, you don't need a powerful tool, you just need the basic one.  A power drill is never going to be good at cutting wood - a basic handsaw is the way to go.  It's all about selecting the right tool for the job.

Looking at MVT, as with all online optimisation programs, the best plan is to build up to a full MVT in stages, with initial MVT trials run as pilot experiments.  Start with something where the basic concept for testing is easy to grasp, even if the hypothesis isn't great.  The problem statement or hypothesis could be, "We believe MVT is a valuable tool and in order to use it, we're going to start with a simple pilot as a proof of concept."  And why not? :-)

Banners are a great place to start - after all, the marketing team spend a lot of money on it, and there's nothing quite as eye-catching as a screenshot of a banner in your test report documents and presentations.  They're also very easy to explain... let's try an example.  Three variables that can be considered are gender of the model (man or woman), wording of the banner text ("Buy now" vs "On Sale") and the colour of the text (black or red).

There are eight possible combinations in total; here are a few potential recipes:


Recipe A
Recipe B
Recipe C
Recipe D

Note that I've tried to keep the pictures similar - model is facing camera, smiling, with a blurred background.  This may be a multi-variate test, but I'm not planning to change everything, and I'm keeping track of what I'm changing and what's staying the same!!

Designing a test like this has considerable benefits: 
- it's easy to see what's being tested (no need to play 'spot the difference')
- you can re-use the same images for different recipes
- copywriters and merchandisers only need to come up with two lots of copy (which will be less than in an A/B/C/D test with multiple recipes).
- it's not going to take large numbers of recipes, and therefore is NOT going to require a large volume of traffic.

Some time soon, I'll explain how to analyse and understand the results from a multi-variate test, hopefully debunking the myths around how complicated it is.


Image credits: 
man  - http://www.findresumetemplates.com/job-interview
woman - http://www.sheknows.com/living 


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