# Should Filters Stay Sticky While Scrolling? A/B Test

Page: https://alidemirbas.com.tr/en/lab/ab-test-library/tests/should-filters-stay-sticky-while-scrolling-ab-test

## Hypothesis

If the filter panel stays on screen while visitors scroll, someone deep in a long listing can change filters without going back to the top. That could help more visitors reach suitable products and raise purchase conversion rate, although the space the panel takes may leave fewer products in view.

## When to run this test

Session recordings with repeated trips back to the top of long listings, filter changes that start only after a long scroll, or heatmaps where the panel is used only on the first screen all suggest visitors are scrolling up just to reach the filters. With a fixed panel working as intended, filters get used mid-scroll and visitors reach suitable products by a shorter route. If visitors reach the filters and still dislike the results, the options are the more likely problem, so look at them first; leave the options unchanged in this test and compare only whether the same panel stays fixed.

## Primary metric

**Purchase conversion rate (CR)**: Compare purchases among eligible visitors assigned to the filter panel when it is usable, over the same follow-up window.

## Other metrics

- **Filter usage rate**: Measure filter use among eligible assigned visitors who can access the panel.
- **Products actually seen**: Count distinct products that enter the viewport in the same list and time window.
- **Listing-to-product click-through rate**: Compare transitions from a product-list impression to a product page.
- **Zero-result rate**: Track searches with no results among those where filters are applied.

## What to check before and during the test

- **Sticky behavior**: Keep the full panel the same and define one fixed sticky rule.
- **Screen space**: Review remaining screen area and product visibility beside or below the panel.
- **Panel design**: Keep panel content and size unchanged; a floating filter button is a different treatment.
- **Trigger**: Set the scroll point where the panel becomes sticky before launch.
- **Device**: Include only layouts where the panel is usable and its behavior differs.

## What to watch when reading the result

- Higher filter usage rate cannot call a winner; purchase conversion rate is the measure. If products actually seen and listing-to-product click-through rate fall, the panel may be crowding out products, so do not build it so large that only a narrow strip is left for the listing.
- Make sure before launch that content and controls under the fixed panel stay reachable and that keyboard focus order still makes sense as visitors tab through it. If a layout fails either check, fix it before you count that layout's result as a gain.
- What this test tells you is limited to this panel, the scroll point you set in advance and the layouts you included. A floating filter button or a different page layout is a separate comparison, so validate it on its own before carrying the result over.
- Purchases happen less often than filter use, so a modest difference can stay unclear for a long time. Before launch, enter the current purchase conversion rate and the lift you would not want to miss into the [sample size calculator](https://alidemirbas.com.tr/en/calculators/sample-size-calculator). Divide the sample it gives per variant by one arm's daily eligible visitors; if the run that implies is too long, this traffic cannot detect the effect you expect.

## Frequently Asked Questions

### Does more filter use mean the fixed panel won?

No. Compare purchases over the same window among eligible assigned visitors on supported layouts. Visible product count and product clicks explain whether the panel reduces browsing space.

### What accessibility risks does a fixed panel create?

It can cover focused content or controls and disrupt keyboard navigation. Check narrow viewports and browser zoom, including remaining product width. There is no universal half-screen limit.

### Which layouts should be included?

Include only usable layouts where the panel variants actually differ. Check product visibility beside or below the panel. Keep filter options unchanged.