I work on a mobile app (ecommerce) which during the purchase path has persistent buttons that are always to the bottom of the screen, regardless of where the view is scrolled, in order to move the user through to the next step.

For example it would be the equivalent to the Amazon app always having a "Buy Now" button stuck to the bottom of the screen no matter where you were scrolled on their product view. Or on the eBay app, having a "Bid" button always showing when you view an item rather than having to scroll to that point in the view.

What I'm wondering is, has there been any research around this type of persistence in actions? My theory is that while it may maximize the number of people who tap the button and go on to the next step since it is always visible, the button always being there may also decrease engagement with the content of the view itself. Haven't been able to find any research on the soundness of this kind of approach.

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    Welcome to the site, @bobfet1! Nice first question. I find it interesting that you think having the button always there might lead to disengagement with the content because I would expect the opposite to be true. You might also try looking for research about blindness to parts of sites that remain static between pages. Aug 23, 2014 at 2:21
  • That's a good point about blindness when there is static content. I'll look into that. In this case, since the mobile screen is small, I worry that primary controls that are fixed on the screen have the effect of appearing to be in the foreground, whereas the content is pushed more into the background and distanced.
    – bobfet1
    Aug 25, 2014 at 18:20
  • I would think the page content should support the fixed (foreground) action items. Ebay/Amazon doesn't care if you've read the page content, as long as you click Bid/Buy... the information is supporting the conversions. If you have, say, credit card information that needs to be filled out before moving on, put "Next" at the bottom. Then maybe if the user needs to back up, give them persistent navigation.
    – Phil Tune
    Aug 25, 2014 at 20:38
  • "Next" is really ambiguous. Try to stay away from ambiguous labeling, because that will confuse more than help.
    – UXerUIer
    Aug 27, 2014 at 14:38
  • In material design there's a component called persistent bottom sheets (material.io/guidelines/components/…), not sure if this is the kind of thing ebay and amazon are using but maybe this is what it is... Jul 24, 2017 at 7:36

1 Answer 1


Good question! While I don't have any knowledge about relevant research, I think that having a button stuck to the bottom screen is not the best option. Here is my rationale:

  1. Button takes valuable space that could instead be taken by product information. Product information is critical for users to make purchasing decisions.
  2. It could be annoying to have this button hanging above the user at all times. Users may feel you just want them to click Buy even if the product doesn't meet their needs.
  3. Bottom of the screen is often used for scrolling the page with a thumb so I think the chance of users accidentally clicking Buy is high. Once users make this mistake and land on the wrong screen, they have to correct the mistake and navigate back. Users don't like to work more and might just leave the site.

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