# Site-Wide Campaign Announcement Bar A/B Test Example

Page: https://alidemirbas.com.tr/en/lab/ab-test-library/tests/site-wide-campaign-announcement-bar-ab-test-example

## Hypothesis

If a real time-limited campaign appears in one fixed banner on every page across the site, more visitors may notice it during their visit. More people seeing it could lift the campaign action completion rate, though the banner takes up space and may be overlooked on repeat visits.

## When to run this test

A time-limited campaign announced only on the home page or the campaign page can leave visitors elsewhere unaware of it; few visits to the campaign page, site searches for the campaign or support tickets from customers who heard about it too late are the warning signs. When the banner does its job, visitors who see it on different pages complete the predefined campaign action more often. Before launch, choose that action, confirm the campaign is real with accurate dates and countdown, and make sure the banner comes down when it ends.

## Primary metric

**Campaign action completion rate**: Choose one campaign action before launch, such as visiting the campaign page or completing an eligible campaign order, and measure it among all assigned visitors. Do not run the test until the action event is defined.

## Other metrics

- **Overall purchase conversion rate (CR)**: Compare purchases or the predefined primary site action among all eligible assigned visitors.
- **Announcement bar click-through rate**: Compare clicks among eligible visitors who see the bar.
- **Bar dismissal rate**: Measure dismissals; a dismissal alone does not prove irritation.
- **Page exit rate**: Compare exits using the same session window.

## What to check before and during the test

- **Presence**: Add one fixed announcement bar to the predefined site-wide page scope.
- **Coverage**: Keep page coverage the same; testing selected categories is a separate experiment.
- **Dismissal**: Use the same close behavior and respect dismissals on later pages.
- **Repeated views**: Use visitor-level exposure history rather than counting every page view as a separate person.
- **Mobile**: Check space taken and access to page content.

## What to watch when reading the result

- A higher announcement bar click-through rate does not settle the test. The predefined campaign action completion rate is the deciding metric; check that overall purchase conversion and page exit rate do not worsen over the same window. Do not read the bar dismissal rate as proof of irritation on its own.
- This test measures only whether the banner is present; if you also change its message, you cannot tell what caused the difference. Read the result by each visitor's exposure history rather than counting every page view as a separate person, and check on mobile that the fixed banner can be dismissed and never permanently covers important content.
- If the result is not clear-cut, first check that assignment stayed consistent across the site and that visitors split between the arms as planned (sample ratio mismatch). Because the campaign window is limited, use the [sample size calculator](https://alidemirbas.com.tr/en/calculators/sample-size-calculator) before launch to find the visitors per arm needed for the effect you care about, and check that eligible traffic per arm during the campaign can reach it.

## Frequently Asked Questions

### What must be decided before the test starts?

Choose one campaign goal, such as visiting its page or completing a qualifying order. The setup is incomplete without that decision. Measure it among all eligible assigned visitors.

### Are more strip clicks enough?

No. Use completion of the predefined campaign goal while monitoring overall conversion and exits over a common window. The strip also occupies page space.

### Do frequent dismissals prove the strip is annoying?

Not by themselves. Allow dismissal and respect it on later pages. Review display history without counting each page view as an independent person.

### What should limited-time messaging disclose?

Use genuine dates and countdowns, and remove the strip when the offer expires. Do not change presence and copy together. Check mobile space usage and content access.