I'm working on several mobile filters with long lists and wondering if this pattern that's been used in most mobile phone contact lists is actually usable? It seems too small to get an accurate press on any letter in the list. What's your take on this? If normally users are using this for their usual mobile tasks on the native OS then it should be a good pattern to adapt, right?

Illustration of the optional index along the right edge

  • Good question! I'm interested to see what responses you get. I asked my Dev colleagues to remove this index from one app that had long lists, because it didn't work very well for a handful of people I observed (in a statistically invalid sample!), and because my lists had a Search box. The iOS human-interface guidelines say the index is optional. See Table View on this page: developer.apple.com/library/ios/documentation/UserExperience/…
    – JeromeR
    Aug 31, 2015 at 6:52
  • I never had a problem with it because you can hold down your finger and scroll to what you actually wanted. Also on android you can hold down and swipe to the left you change the second or third letter. You can hold down, scroll to M, then move a bit to the left and change the second letter and thus accessing the Part where the Entries begin with MI and if you really have an enourmouse collection you can do this more often until you got "MICE" or whatever you were searching for. Bit at this point you propably would've used the search function long time ago
    – BlueWizard
    Aug 31, 2015 at 14:33
  • Jonas yes you probably didn't have any problem using it. Most of us here are power users but I'm curious if this is intuitive to the average user
    – Blue Ocean
    Sep 1, 2015 at 3:13

2 Answers 2


Personally I use this all the time. While it would seem too difficult to have accuracy these are actually treated like a smart scrollbar that scrolls not by pixels but by letters. Users are able to drag down on the letters to pinpoint the letter that they would like.

If you have the resources to build this in your project I would say that it would be highly beneficial.

Like Jonas Dralle said this feature is not just available on ios but also on android (other systems too). Depending on how big your lists are it may be better to add advanced search rather than this (or maybe in addition to this). It all depends on what kind of data you are handling, the larger and more complex the data the better it would be to use search. If the data is too small users might feel overwhelmed by the extra ui elements.


I've used both Android and iOS, out of those two I find the Android alphabet scroller easier to use.

It's all because as soon as you press the scroll bar, the letter that's selected appears on the center of the screen. (Position might change based on the device)

enter image description here

This tells me,

  1. I have selected the contact scroller and nothing else.
  2. I can drag the scroller and the letter on the center tells me exactly where I'am.

This feature solves your problem of the letters being too small to get an accurate press.

As for whether users would understand an alphabet scroller or not -

  • Younger audiences are getting better at navigating applications and finding how things work. Having spent longer hours on smart devices browsing different applications, they would possess the experience needed to identify how this would work.
  • As for other users, any user who knows or has used a contact book or something similar are likely to know what it is and what it does. enter image description here

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