myths, lies and illusions of ab and split testing
TRANSCRIPT
Myths, Lies and Illusions of Split Testing
@OptimiseOrDie
@OptimiseOrDie
• UX, Analytics, Split Testing and Growth Rate Optimisation
• Started doing testing & CRO 2004
• Split tested over 45M visitors in 19 languages
• 67+ mistakes I MADE with AB testing
• Like riding a bike…
• Optimise your optimisation? Get in touch!
Myths, Lies and Illusions of Optimisation
1. Optimisation and Testing are the same
2. Optimisation and Testing are easy
3. Statistical significance tells you when to stop
4. High traffic always makes tests shorter
5. It’s all about Conversion Rates
6. You don’t need to test the test
7. Your tests will give you the quoted lift
8. High traffic pages give the best tests
9. It’s about getting all your tests to win
10. Optimisation is only about websites
@OptimiseOrDie
11. Segmentation will tell you what happened
12. You can’t run multiple simultaneous tests
13. Testing is great for settling arguments
14. You can spot trends early on in a test
15. More test volumes = better results
16. Your tests tell you truths that last forever
17. You can test even on low traffic sites
18. Other people’s tests are ‘Best Practice’
19. Doesn’t involve changing the way you work
20. Testing makes you a Data Scientist
#fail
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@OptimiseOrDie1. Testing & Optimisation are the same thing
Testing
Optimise
What is CRO/Optimisation?
• “Using Analytics data and Customer feedback to improve the performance of your website.”
• “Finding out why visitors aren’t converting and then resolving these issues.”
• “Running loads of crappy split tests randomly until the heat death of the universe”
@OptimiseOrDie
What is my definition?
“A structured, systematic and continuous application of techniques that are used to discover, quantify and prioritise issues.
These can be turned into hypotheses to drive experiments and opportunity in the following business outcomes:”
• Increased revenue or profitability
• Increasing LTV, loyalty, NPS/Sat scores, Kristoffer Potential
• Removing cost from the business or contact center
• Higher productivity or labour flexibility
• Delighting customers
• Reduced development effort
@OptimiseOrDie
What Optimisation is NOT!• A way to change things you (or others) hate
• A methodology for running split tests
• A guarantee of increased conversion
• A methodology for looking at analytics data
• A rescue for silo-bound or non-agile design or development processes
• A way to trick people into buying
• A bolt-on – it IS the process
@OptimiseOrDie
Optimisation is a:• Way of joining the worlds of Customer insight, UX,
Analytics, Split testing and Business Strategy
• Overarching Design and development process which prioritises work around opportunity
• Strategic, not tactical, response to wasted development effort or product change
• Way to create a deep and meaningful connection between the team, customers, business and the outcomes of making product changes
• The killer app to remove ego, opinion, assumptions, cherished notions or ‘we just do it that way’ from decision making.
• More powerful method than UX research or analytics alone, in guiding the directionality of product change
@OptimiseOrDie
Optimisation includes these:• Qualitative research
• Analytics, Quant analysis and insight
• UX inspection and discovery
• Competitive Intelligence
• Priority based opportunity
• VOC, Surveys and Customer Satisfaction (NPS)
• Call tracking & Call centre optimisation
• AB testing
• Multivariate testing
• Photography optimisation
• EEG / ECG / Galvanic response@OptimiseOrDie
• Web performance tuning
• Forms analytics
• Eye tracking
• Market research
• Big & Unstructured data analysis
• PPC optimisation
• Session replay analysis
• Customer journey mapping
• Ethnographic (diary) study research
• Cross device, platform and channel insight
• Email optimisation
2. Optimisation & Testing are EASY
Surely you just add Javascript?• This work is harder than anything I’ve ever done!
• You all have expensive & limited resources for testing - like Airport take-off slots
• You MUST make use of these efficiently
• You HAVE to balance resource cost with opportunity by prioritising carefully
@OptimiseOrDie
• You’re doing the equivalent of drug trials!
• For large OR small companies, the instrumentation, analytics, tools setup, plan design, test methodology and analysis cannot be ‘done later on’. It’s not complex but it is vital.
• The best companies have a structural shell (process, methodology, management) around their activities
• If you’re not optimising the process continuously (Kaizen), you won’t increase your velocity of iterations.
• Optimise the Optimisation
3. Statistical significance tells you when to stop
@OptimiseOrDie
The 95% Stopping Problem
@OptimiseOrDie
• Many people use 95, 99% ‘confidence’ to stop
• This value is unreliable and moves around
• Nearly all my tests reach significance before they are actually ready
• You can hit 95% early in a test (18 minutes!)
• If you stop, it could be a false result
• Read this Nature article : bit.ly/1dwk0if
• Optimizely have changed their stats engine
• This 95% thingy – must be LAST on your stop list
• Let me explain
The 95% Stopping Problem
@OptimiseOrDie
Scenario 1 Scenario 2 Scenario 3 Scenario 4
After 200 observations
Insignificant Insignificant Significant! Significant!
After 500 observations
Insignificant Significant! Insignificant Significant!
End of experiment
Insignificant Significant! Insignificant Significant!
“You should know that stopping a test once it’s significant is deadly sin number 1 in A/B testing land. 77% of A/A tests (testing the same thing as A and B) will reach significance at a certain point.”
Ton Wesseling, Online Dialogue
The 95% Stopping Problem
@OptimiseOrDie
“Statistical Significance does not equal Validity”
http://bit.ly/1wMfmY2
“Why every Internet Marketer should be a Statistician”
http://bit.ly/1wMfs1G
“Understanding the Cycles in your site”
http://mklnd.com/1pGSOUP
4. High Traffic always means short tests
@OptimiseOrDie
Business & Purchase Cycles
@OptimiseOrDie
• Customers change• Your traffic mix changes• Markets, competitors• Be aware of all the waves• Always test whole cycles• Don’t exclude slower buyers• When you stop, let test
subjects still complete!
Start Test Finish Avg Cycle
• TWO BUSINESS CYCLES minimum (week/mo)
• 1 PURCHASE CYCLE minimum
• 250 CONVERSIONS minimum per creative (e.g. checkouts)
• 350 & MORE! if response is very similar
• FULL WEEKS/CYCLES never part of one
• KNOW what marketing, competitors and cycles are doing
• RUN a test length calculator - bit.ly/XqCxuu
• SET your test run time , RUN IT, STOP IT, ANALYSE IT
• ONLY RUN LONGER if you need more data
• DON’T RUN LONGER just because the test isn’t giving the result you want!
@OptimiseOrDie
How Long? Simple Rules to follow
5. It’s ALL about Conversion Rate
@OptimiseOrDie
It’s all about the business
@OptimiseOrDie
• You’re optimising a business here, not a page or site
• Tricking, pushing or persuading people at a superficial level to take an action is not a viable strategy
• Your optimisation strategy is a series of steps, not a tool
• Testing is about learning, not converting.
• Tests that fail to tell you anything (regardless of outcome) are a failure themselves
• If you don’t shift the business goals, your optimisation and testing budget will be threatened
6. You don’t need to test the test – just go
@OptimiseOrDie
Browser testing www.crossbrowsertesting.com
www.browserstack.com
www.spoon.net
www.saucelabs.com
www.multibrowserviewer.com
Mobile devices www.appthwack.com
www.deviceanywhere.com
www.opendevicelab.com
Read this article bit.ly/1wBccsJ
7. The test result gives the promised lift
@OptimiseOrDie
The result is a range
@OptimiseOrDie
• Version A is 3% conversion
• Version B is 4% conversion
• Yay! That’s a 25% lift
• Let’s tell everyone
• When it goes live, you get 5.7%
• That’s because it was A RANGE
• 3% +/- 0.5
• 4% +/- 0.4
• Actual result was 3.5% for A
• Actual result was 3.7% for B
8. Testing is best on high traffic pages
@OptimiseOrDie
Think like the CEO of a department store!
If you can’t refurbish the entire store, which floors or departments will you invest in optimising?
Wherever there is:
• Footfall• Low return• Opportunity
Ecommerce
Bounce
Search or
Category
Product
Page
Add to
basket
View
basket
Checkout
Complete
@OptimiseOrDie
8. Testing is best on high traffic pages
@OptimiseOrDie
8. It’s all about prioritisation!
9. It’s all about WINNING test results
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Failing is good
@OptimiseOrDie
• Tests that are ‘about the same’ are a failure
• They’re also very hard to call
• That means you have to be BOLD not conservative
• A test that comes out negative is NOT a failure
• If a ‘negative’ test teaches you something, it’s a success!
• If you hit 40/50/60% failed tests, that’s fine
• If you aren’t failing regularly, you’re not BOLD enough
• Success is about the number of tests you finish each month, and what you learn from them
We believe that doing [A] for People [B] will make outcome [C] happen.
We’ll know this when we observe data [D] and obtain feedback [E]. (reverse)
@OptimiseOrDie
10. Optimisation is only for Websites
@OptimiseOrDie
Optimisation is just for websites
@OptimiseOrDie
• Service Design (Airbnb)
• Onboarding flows with emails
• Email templates
• Apps – testing, debugging, tracking
• Phone tracking and call centre optimisation
• Social, Display, TV, Video and other advertising
• Print adverts, Direct Mail
• In-store promotions
• Product manuals, guides, interfaces
• EVERYTHING has elasticity – just find it
• Even Multi-variate call centre scripts
11. Segmentation will explain things
@OptimiseOrDie
Segmentation explains stuff
@OptimiseOrDie
• Beware of small sample sizes
• A = 350 conversions
• B = 300 conversions
• A Conversions for Safari = 20
• B Conversions for Safari = 25
• Only needs 2 people to change that from 25% lift to 14%
12. You can’t run concurrent split tests
@OptimiseOrDie
Oh yes you can, with GA!
@OptimiseOrDie
• If you push events or variables into GA, you can report on behaviour for A or B (or any variations).
• If you do it that way, you can easily run multiple tests on different page targets simultaneously.
• You grab AAA, AAB, ABA, ABB and analyse.
• Test subjects get a recipe of tests, so one caveat
• If you pick things that clash or jar the experience
• If you have $5 delivery but then $2 in another test
• Apart from that, it’s fine to run these
• They tell you about the right experience recipe across several pages being optimised in concert
13. Testing is great for settling arguments
@OptimiseOrDie
14. You can spot trends early in a test
@OptimiseOrDie
You can spot trends early
@OptimiseOrDie
• Tests are volatile in the early stages
• Watch but shut your mouth and wait
• Keep an eye on any odd behaviour
• Be patient!
15. More tests = Better results
@OptimiseOrDie
More tests = Better results
@OptimiseOrDie
• Increasing volume without optimising velocity
• Not optimising the process means it scales badly
• If you put garbage in, you’ll get garbage out
• Ramping up before you have it tuned is crazy
• Get the team, process, project management, methodology, toolkits, selling and PR nailed first
• THEN optimise and scale
• I know that one UK retailer is doing 140 per month!
• That’s LOW compared to some companies I work with
• Big companies doing 2 a month? Meh.
16. Each test is a truth FOREVER
@OptimiseOrDie
Tests are a Truth Forever
@OptimiseOrDie
• Traffic changes
• Prices change
• Product mix changes
• Advertising evolves and changes
• Markets are different
• Customers have changed
• Competitors or regulatory landscape moves
• Things happen outside of your control
• You need to revisit tests or ITERATE
• Always be trying to beat the new winner, not basking in the glory of a test you ran 9 months ago
• The lift may have vanished
• Schrodinger’s AB test
17. Testing is fine on Low Traffic sites
@OptimiseOrDie
Testing is fine on low traffic sites
@OptimiseOrDie
• Yes, if you estimate your minimum testing unit
• This is the time to AB test a sample of say 250 conversions, with the rules I set earlier.
• A payday loan company? 2 months minimum!
• Run the calculations
• Check the test length
• If it takes like, 8 million years, what can you do?
• Read this or download my AB testing decks:
bit.ly/1umy5Y6
18. Other people’s tests are Best Practice
@OptimiseOrDie
“STOP copying your competitors
They may not know what the f*** they are doing either” Peep Laja, ConversionXL
Tests you see online?
@OptimiseOrDie
• Your customers are not the same
• Your site is not the same
• Your advertising and traffic is not the same
• Your UX is not the same
• How the f*** do you think it guarantees a result?
• Use them to inform or suggest ideas
• They’re like the picture on meal packets
• Serving Suggestion Only
19. Testing makes you a Data Scientist
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20. Testing and Innovation is a plugin
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WE’RE ALL WINGING IT
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What I thought
I knew in 2004
Reality
2014 Headspace
What I
KNOW
I know
Me, on a
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Rumsfeldian Space
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The 5 Legged Optimisation Barstool
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READ STUFF
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#5 : FIND STUFF
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#12 : The Best Companies…
• Invest continually in analytics instrumentation, tools, people
• Use an Agile, iterative, cross-silo, one team project culture
• Prefer collaborative tools to having lots of meetings
• Prioritise development based on numbers and insight
• Practice real continuous product improvement, not SLEDD*
• Are fixing bugs, cruft, bad stuff as well as optimising
• Source photos and content that support persuasion and utility
• Have cross channel, cross device design, testing and QA
• Segment their data for valuable insights, every test or change
• Continually reduce cycle (iteration) time in their process
• Blend ‘long’ design, continuous improvement AND split tests
• Make optimisation the engine of change, not the slave of ego
* Single Large Expensive Doomed Developments
THE FUTURE OF TESTING : www.conductrics.com