The theory is unusually clear: the interaction costs are substantially different for content above vs. below the fold. It’s nice when there’s empirical data to support a theory. And, that evidence is abundantly available in the case of the page fold. We have observed countless users in qualitative studies having their behaviors impacted by the fold — often for the worse. Websites didn’t prioritize above-the-fold content appropriately. Users stopped scrolling on the website before finding the information they needed. Or, they didn’t realize that there was more information waiting for them below the fold. There’s also quantitative evidence: in an analysis of 57,453 eyetracking fixations, it was found that there was a dramatic drop-off in user attention at the position of the page fold. Elements above the fold were seen more than elements below the fold: the 100 pixels just above the fold were viewed 102% more than the 100 pixels just below the fold. (See Heat Map Image below)
Content below the fold does get some looks, but not nearly as many as the content above the fold. A heat map shows 57,453 eyetracking fixations across a wide range of pages, excluding search and search-results pages. Red indicates where users looked the most; yellow where they looked less. White areas got virtually no looks. The top black stripe indicates the page fold in the study; subsequent black stripes represent each additional screen after scrolling. An aggregate A second set of data comes from Google’s analysis of display advertising (PDF) across a huge number of websites. The study looked at how “viewable” an advertisement was, with viewability defined as 50% of the ad’s pixels being on-screen for one second. Advertisements just above the fold had 73% viewability, whereas ads just below the fold had 44% viewability. In the Google study, the drop-off caused by the fold was 66%, because that’s how much more ads just above the fold were visible, compared with ads just below the fold.
Why did Google measure the fold’s impact at 66% when we measured it at 102%? The explanation lies in the two different metrics employed. Google measured whether an ad was displayed on the screen, so that the user might see it if they happened to look directly at that spot. We measured where people actually looked on the screen AND how much time they spent looking. The two quantitative studies produce slightly different estimates of the fold’s impact on the user experience. But both numbers are big: we’re not talking a 5% difference or a 10% difference between information above vs. below the fold. The difference is on the order of 66%–102%!
If you want a single number as our best current estimate, let's take the mid-point of this range: 84% is the average difference in how users treat info above vs. below the fold. And, that is HUGE. Believe in the fold. It’s there, and the user experience changes drastically at that spot.