Usability findings

Meridian Store Study

5 participants · A/B: Current checkout vs New checkout · August 7, 2026

93%
task success
67.5
SUS (of 100)
5.7
avg ease (of 7)
3
tasks measured

1. What we tested

We tested how easy it is for users to complete a purchase on an e-commerce site. Participants were asked to find a wireless keyboard under $50, apply a discount code (SAVE10), and complete checkout using a saved credit card. Five real users completed the full task in two different versions of the checkout flow — the current design and a new, redesigned version.

2. How it went overall

The task was completed successfully by all participants in the new checkout design, but the current design had serious problems. In the new checkout, users completed the entire task in about 3 minutes on average — all steps went smoothly. In the current checkout, users struggled especially with applying the promo code, where two out of three participants failed or gave up. The new design reduced task time and improved user confidence, with a clear win in both speed and ease.

3. What got in people's way

Hidden promo code field in accordion — a critical flaw

The promo code field was hidden behind an “Order options” accordion, making it invisible to most users. Participants said they didn’t see any place to enter a code, and one directly questioned, “Why would they hide the coupon field inside an accordion? Nobody will find that.” This design flaw affected every session and caused major frustration. It’s not just hard to find — it’s a design mistake that makes users feel misled.

> One participant said: “I don’t see any place for a promo code.”

> Another said: “There’s nothing here that says promo or discount or coupon anywhere.”

This is a critical problem because users don’t know where to look, and the system doesn’t help them find it.

Mismatch between what users thought and what actually happened — a critical failure

Users rated the promo code step as easy (average 4.8 out of 7), but many actually spent a long time trying to find it or gave up. In one session, a participant rated it as 5/7 easy but gave up after 289 seconds — more than four minutes. Another said, “Honestly I would just pay full price at this point. I give up on the code.” This shows a dangerous gap: users don’t realize how hard the step is, and the design fails to show them what’s missing.

This is a critical issue because it means users are misled by the system — they think it’s simple, but it’s not. This leads to frustration, lost sales, and trust issues.

4. Task by task

5. What we recommend

1. Replace the hidden promo code field with a visible, prominent input box — move it to a clear location on the cart page, not behind an accordion. This will help users find it instantly and prevent confusion and frustration. The new design already shows this works — users completed it in half the time.

2. Fix the mismatch between user perception and actual difficulty — users think the promo code step is easy, but it’s not. We must redesign the flow so that users can see the field, know where to enter it, and get feedback if they make a mistake. This will build trust and reduce drop-offs.

3. Improve error messages during checkout — when users get an error like “402,” the system must explain what went wrong and what to do next. Clear, helpful messages prevent confusion and help users recover quickly. The new design already scores much higher in usability (93.8 vs 50.0), showing that these changes make a real difference.

Metrics

Task outcomes
Find product5/5 succeededApply promo code4/5 succeededCheckout and pay5/5 succeeded
SuccessWith difficultyFailed / gave up
Time on task
Find product40s · n=5Apply promo code88s · n=5Checkout and pay61s · n=5
One attemptMedianPast the axis

2 attempts ran past the axis (longest 4m 49s, against an axis ending at 2m 01s), marked at the right-hand edge. The scale follows the bulk of the attempts so the rest stays readable.

Tasks with fewer than 8 timed attempts show every attempt as a dot rather than a box: quartiles drawn from a handful of measurements would suggest more precision than the data carries.

System Usability Scale
68 (industry avg)P01 Maya50P02 Devon25P03 Priya75P04 Jordan100P05 Sam87.5Average 67.5 of 100
Ease per task (SEQ, 1-7)
Ease — Find product6.4 / 7Apply the discount code SAVE10 atcheckout4.8 / 7Complete the purchase with thesaved credit card6 / 7
Time on task by design
Find productCurrent checkout: 44s · n=3 · 3/3New checkout: 36s · n=2 · 2/2Apply promo codeCurrent checkout: 3m 18s · n=3 · 2/3New checkout: 55s · n=2 · 2/2Checkout and payCurrent checkout: 74s · n=3 · 3/3New checkout: 43s · n=2 · 2/2
Current checkoutNew checkoutMedianPast the axis

2 attempts ran past the axis (longest 4m 49s, against an axis ending at 2m 01s), marked at the right-hand edge. The scale follows the bulk of the attempts so the rest stays readable.

Designs with fewer than 8 timed attempts show every attempt as a dot rather than a box. Splitting participants between designs halves the attempts behind each one, so this is the usual case in a moderated A/B study — and the point at which a difference between two designs is easiest to over-read.

SUS by design
Current checkout50 / 100New checkout93.8 / 100
Ease — Find product by design
Current checkout6 / 7New checkout7 / 7
Apply the discount code SAVE10 at checkout by design
Current checkout3.7 / 7New checkout6.5 / 7
Complete the purchase with the saved credit card by design
Current checkout5.3 / 7New checkout7 / 7

Highlight clips

Moments the researcher marked. Play inline.

P2 gives up on the promo code · P02 Devon
Error 402 confusion at payment · P02 Devon
"Nobody will find that" - hidden promo field · P03 Priya