The question behind the interface
The product page, basket and checkout reveal different parts of the offer. This uncertainty can affect willingness to continue. Research should examine which information the intended shopper needs and when.
A proposed direction
Show the known total and explain any amount that still depends on location. Make guest checkout visible and keep error recovery close to the affected field.
Review before paying
Example basket: items €40. Delivery depends on destination. See the final total before payment.
Choose delivery →- Review basket
- Choose delivery
- Confirm total
Static design example. The depicted action is not an interactive product control.
How I would investigate it
Ask a participant to establish the total price and expected delivery before committing. Use a test shop without a live payment method. Observe whether an unknown charge is understood as an estimate, an omission or a final total.
Before recruiting, we would agree the decision the study must support, the people whose experience matters and a realistic task. The session plan would specify a safe starting state and avoid leading the participant towards the proposed solution. Relevant access needs, consent and handling of research material would be included in the scope.
The tradeoff to examine
A simple total is useful only if accurate. Delivery options may depend on address, stock or fulfilment rules. Explain the dependency rather than presenting a made-up certainty. A test should also check that fixing an error does not erase valid information.
What would count as useful evidence?
Understanding of total cost, ability to use guest checkout, correction of invalid details and confidence about whether payment has occurred.
Record the actions, misunderstandings and assistance required. Keep participant comments separate from interpretation and show important exceptions as well as patterns. A revised design would remain a proposal until it had been evaluated; task completion in a small qualitative study would not establish a population-wide conversion rate.