Guide · Program strategy · 2 min read

CRO prioritization: How to pick which test to run first

How to prioritize A/B test ideas with the PXL framework: the ten criteria, a worked example, how it compares with ICE, PIE and RICE, and where any scoring model breaks.

Every team has more ideas than testing capacity. Without a shared method, the loudest or most senior opinion wins. PXL, a framework created by CXL, replaces opinion with specific questions.

The ten PXL criteria

Group Question Score
Impact Is the change above the fold? 1 / 0
Impact Is it noticeable within 5 seconds? 2 / 0
Impact Does it add or remove an element? 2 / 0
Impact Is it designed to increase user motivation? 1 / 0
Impact Does it run on high-traffic page(s)? 1 / 0
Evidence Does it address an issue found in user testing? 1 / 0
Evidence …found in qualitative feedback (surveys, polls, interviews)? 1 / 0
Evidence …found in digital analytics? 1 / 0
Evidence Is it supported by heatmaps or eye tracking? 1 / 0
Ease Under 4 hours = 3, up to 8 hours = 2, under 2 days = 1, more = 0 3–0

The maximum is 14. Binary answers stop people hedging with a “6 out of 10”, and the evidence questions mean an idea with no research behind it cannot score highly.

A worked example

Hypothesis: Because session recordings and an exit survey show shoppers leaving checkout when shipping appears, showing the delivery cost on the product page will reduce checkout abandonment.

Above the fold (1) · noticeable (2) · adds information (2) · motivation (1) · high traffic (1) · user testing (0) · qualitative (1) · analytics (1) · heatmaps (0) · ease, about 6 hours (2) = 11 / 14.

Score your own backlog with the PXL calculator: it ranks ideas and exports a CSV.

PXL versus ICE, PIE and RICE

  • ICE (impact, confidence, ease) and PIE (potential, importance, ease) are quick but rely on subjective 1–10 ratings that vary between people.
  • RICE adds reach and is popular in product teams; it still needs an impact estimate.
  • PXL trades nuance for consistency: concrete questions, mostly binary, weighted towards evidence.

Customize it, as CXL intends

CXL explicitly recommends adapting PXL. Common additions:

  • “Complies with brand and accessibility guidelines” (1/0)
  • “No SEO risk” for content-heavy sites (1/0)
  • “Affects the primary outcome directly” (1/0)

Keep the changes written down so scores stay comparable over time.

Limits of any scoring model

  • Scores rank candidates; they don’t forecast results.
  • Criteria are heuristics, not empirically calibrated weights.
  • Ties are common: break them with strategic fit and dependencies.
  • Re-score when new evidence arrives in the next Wonder phase.

Frequently asked questions

What is the PXL framework?

PXL is CXL's prioritization framework for A/B test ideas. It replaces broad 1-10 ratings with specific questions, mostly scored 0 or 1, with extra weight for noticeability, adding or removing elements, and ease of implementation.

How is PXL different from ICE and PIE?

ICE (impact, confidence, ease) and PIE (potential, importance, ease) ask for broad subjective ratings. PXL asks concrete questions, such as whether the issue was found in user testing, which makes scores more consistent between people.

Does a high PXL score mean the test will win?

No. PXL decides which hypotheses are stronger candidates to test first. Only the experiment tells you the result.

Sources

  1. PXL: A Better Way to Prioritize Your A/B Tests. CXL. Accessed 4 November 2026.
  2. WXM: the Wave Experimentation Model. Wavesy. Accessed 4 November 2026.

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