What is A/B Testing?
In an A/B test, traffic is split randomly across two (or more) versions of a page, email or ad - variant A against variant B. One clearly defined target metric (click, signup, purchase) is measured. The version with the significantly better result wins.
Statistical significance is decisive: a 51-to-49 split across 100 visitors is noise, not a result. A valid test needs sufficient sample and runtime, otherwise fluctuations get misread as insights - the most common mistake in practice.
A/B testing is core to conversion-rate optimisation, but not an end in itself. You test what carries a hypothesis ('a shorter form raises completions'), not random button colours. Good teams test few, well-reasoned variants - not a hundred arbitrary ones.
Why does A/B Testing matter?
A/B testing replaces opinion with evidence. Instead of arguing in a meeting over the better headline, the market decides - and every improvement applies to all future traffic.
A/B Testing in practice
- 01Headline A 'Book a demo' against B 'Try for free' - B lifts click rate by 30%.
- 02Two subject lines in an email send, the winner goes to the rest of the list.
- 03At 200 visitors almost nothing is significant, at 20,000 even small differences are.
From the journal
- Pricing on your website? The case for and against, from a conversion perspectiveOne camp fears that public pricing gives away negotiating room. The other quietly loses enquiries to competitors whose price is one Google search away. This piece sorts out what the 2026 data says: how many buyers walk away when prices are missing, who actually publishes them - and when keeping them private remains legitimate.
- Attribution in 2026: what you can actually measure - and what you can'tYour dashboard says Google, your customer says podcast - and both mean the same enquiry. Attribution promises clarity about which channel sells, and in 2026 it mostly delivers one thing: a precise-looking number on shaky ground. This piece separates what you can genuinely measure from what merely looks measured.
