This week: a new formula for powering switchback experiments, why good metrics need to be able to surprise you, and what "done" actually means when you're shipping AI features. Plus the UK government using experimentation to fix public services.
And as always: open roles (993!), upcoming events, and something that made me smile.
Convert—A/B tests & personalization for growth teams
Experimentation Jobs—Find your next role
Good metrics maximize surprise
By Zach Flynn — If your metric is guaranteed to go in the direction you want, you’re running propaganda, not an experiment. Good experiment metrics can go either way, and let customer behavior decide the outcome. READ
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[Paper] Powered switchback experiments, or not?
By Sergei Pankratev (DoorDash) — Platforms use switchback experiments to avoid network effects, but had no formula to calculate statistical power. This paper fixes that. It also explains why switchback experiments require much more data than we think to achieve adequate statistical power. READ
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Testing a different way to improve complex public services
By Tom Wynne-Morgan (UK Government Digital Service) — Most (public service) transformation fails not from lack of skill, but because no single team controls all the constraints that matter. GDS/CustomerFirst is testing a model: small, time-limited, multidisciplinary teams that surface constraints and test assumptions before committing to structural change. READ
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What “done” means when you’re shipping AI features
By Jeff Gothelf — The definition of “done” needs to be rewritten: write acceptance criteria as probability ranges, define your failure triage before you launch, and make sure you can rollback if needed. READ
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Last week’s favourite:
[Paper] Estimating the value of Evidence-Based Decision Making
By Abadie, Agarwal, Imbens et al. (MIT/Stanford/Amazon) — How much is running experiments actually worth? This paper builds a framework to calculate it. Using empirical Bayes on 4,8k+ Upworthy A/B tests, they show that standard p-value decision rules leave ~27–30% of attainable value on the table. READ
Axel Hommenga invited me to the Recruitment Experiments podcast. We talked about the role of job boards in general and Experimentation Jobs specifically. In Dutch, though.
If you like this episode, make sure to subscribe to the podcast. Or discover other podcasts via the Experimental Mind curated podcast feed.
Find 993 open roles on ExperimentationJobs.com. This week’s featured roles:
Senior Front-end Developer (Experimentation) at Creative CX (London, United Kingdom)
Senior Data Scientist – Personalisation & Insights at Mapp Digital (Germany or United Kingdom)
Head of Marketing Experimentation & Growth – InsurTech Start-up at onpier (München, Germany)
Conversion Rate Optimization (CRO) Lead at Spiko (Paris, France)
CRO & Product Manager E-Commerce at De Koffiejongens (Bussum, Netherlands)
A running list of upcoming events. Subscribe here. (👋= join me, 🎁= discount)
👋10 Jun: Best in Test Awards (online)
🆕11 Jun: Berlin Experimentation Meetup #14 (Berlin, Germany)
🎁15 Jun: Advanced Topics in Practical A/B Testing with Ronny Kohavi (online,
$1,199$999 USD)🆕16 Jun: Process Mining 101 (online)
17 Jun: TLC Panel: Accessibility, AI Discoverability, & SEO with Shirley van Haalem, Alisa Scharf, and Sani Manic (online)
23 Jun: Causal Summit (online)
🔥26 Jun: Deadline shortlist submission Experimentation Heroes
👋16 Jul: Experimentation Culture Awards (online)
9-10 Sep: Women in Experimentation Summit (online)
👋24 Sep: Experimentation Elite Awards (London, UK)
👋5 Nov: Experimentation Heroes (Amsterdam, Netherlands)
We want innovation, but without the risk of failure. We want bold thinking, but look for the safe answers. We need to get better at dealing with uncertainty. Looking for growth? Become comfortable with uncertainty.
If this newsletter sparked something and you want to talk it through, a few ways I help:
Scale experimentation
Strategy, setup, metrics, and ways of working for teams that want more impact.Careers and hiring
Support with your next role, or help finding and hiring strong experimenters.Quick sparring
A fresh outside perspective on your ideas, roadmap, or experimentation setup.
Interested?
Just hit reply and tell me what you’re thinking about.
Have a great week — and keep experimenting.
Thanks, Kevin

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