CRO Diary · a conversion specialist's working notebook entries reviewed weekly
CRO Diary

More sales from the traffic you already have

Diagnosis

Your Theme's Core Web Vitals Swing 10 Points a Month Without a Code Change

Merchants ask which theme is fastest as if speed were a fixed property of the code, but tracking five themes across six months of CrUX history shows the pass rate for a single unchanged theme can move 10 points in a month, which means the question itself is broken.

Oct 30, 2026 · latest entry

More from the diary

Follow the diary →

Product Gallery Options in Six Themes: Zoom, Video and Variants

Merchants asking for a gallery comparison usually get marketing copy instead of the actual setting names, so this piece reads the schema files of six Shopify Theme Store themes and reports what each gallery-adjacent setting is called, what it defaults to, and where it lives.

Benchmarks

Shop Pay and Express Checkouts: What the Published Data Claims

The usual pitch treats Shop Pay as a conversion lever on its own, but the published retail and checkout-form data only supports a narrower claim about field count and quarter over quarter share, and this piece settles what that narrower claim actually is.

Benchmarks

Quarterly CRO Benchmark: CrUX Numbers for Top Shopify Stores (Q4)

Merchants read Core Web Vitals pass rates as a verdict on a theme's speed, but the field data from real visitors shows the gap between the best and worst theme on the same platform is wide enough that the theme name alone tells you almost nothing.

Diagnosis

Pricing Psychology on the Product Card: What Tests Actually Show

Merchants assume charm pricing and tiered plans are decided by gut feeling, but Shopify's own pricing page shows the anchoring is built into fixed numbers like €24, €69, €289 and €2,100, which is a structural pattern rather than a hunch.

Benchmarks
2026 Across five themes with monthly CrUX history from March 2026 to August 2026, the share of stores passing all Core Web Vitals moved by 10.0 points at the median within a single theme, and by as much as 12.3 points for the most volatile one.
, All six themes checked, Allure (UTD), Boutique, Gain, Impression, Ultra and Victory, ship the same quick view setting id, is_quick_view_enabled, but the number of settings clustered around it ranges from 8 in Allure to 25 in Victory.
29 Across 29 themes the median review count is 48, but the range runs from 1 to 590, so the average tells a merchant nothing about a typical listing.

The sections