Best practice for scrolling and orientation within non-touch displays: line-wise vs. page-wise scrolling?

Question

I've been searching the web for quite some time now, but either I am always using the wrong keywords or there is no literature out there on this topic...

What is the best way for a user to orientate himself in a list with e.g. 8 list items of which only 4 items are shown at a time?

• Leave the focus frame at the bottom and only show the fifth item when scrolling down (line-by-line)?

or

• Set the focus frame to the top position and show items 5-8 when scrolling down (page-by-page)?

Do you know of any studies that might help me out? Thank you!

Answer 1

As always it is always best to let the user decide, and offer them the option, as when scrolling on a PC, to choose a line scroll (analogous to using the cursor keys) or a page scroll (analogous to PgUp and PgDn).

Each method has its merits:

• Line-by-Line gives the user a less sudden flash to a new environment, and it easier on the eyes.
• Page-by-Page offers a more rapid, flick through the document option. Useful for scanning a document, or returning to the point where the reader left off, during the previous reading

It is always a good idea to give the user reference, as to where the last line was prior to scrolling. So, using your example of a list containing eight items of which only four items are shown at a time, if you were to do a page-by-page scroll then from lines 1-4, then show 4-7, and finally 7-8.

Line scrolling can employ scrolling by half lines to offer a similar smoother effect.

The book, The Essential Guide to User Interface Design: An Introduction to GUI Design By Wilbert O. Galitz offers some good tips regarding scrolling, pages 179-180. Unfortunately I can not paste the quote here, but follow the link.

Answer 2

"As always it is always best to let the user decide"

I'm not totaly agree with that. It's the best way to make the user feeling indecisive. Sometime the best way to help a customer to use something is to offer him only one option (memory retention).

Bloc by bloc (meaning moving the all number of items diplayed on the visible list at a time) is easier to understand, quicker to use and it's common nowadays, but it have to be animated to understand it easily.

Answer 3

I would not show 1-4, then 5-8, etc. With this, you will enforce context to the user. Usually, list items are ordered, which makes the comparison between item 4 and 5 useful, most likely. But with "locking" the user to 1-4 and 5-8, users cannot do that.

Grouping will enforce the user to remember the items that are now gone on the screen. The possible result is frustration, while the other way requires "more scrolling", which multiple tests proved as learned behavior.

In my experience, especially on mobile, users do no longer have problems with scrolling - while enforcing my will to the user will nearly always make them feel uncomfortable.

Answer 4

Is there no way to have both? The situation that immediately came to mind was the DVR for my TV at home. When looking at the channel guide, the cursor buttons (surrounding the "OK" button on the remote) move up and down one line at a time, while the channel select rocker becomes a "page up"/"page down" control.

Anyway, if you're going to implement page-based viewing, the easiest way for the user to stay oriented is to advance the screen by one line less than a full page, so that the row that had been on the bottom of the previous page is now at the top (or vice-versa when paging up). So, if you have 8 items and are viewing 1-4, page down should show 4-7, and if you're looking at 5-8 and page up, you should see 2-5. Yes, that means it takes a second page command to show all of what should be 2 even pages' worth of data, but having the total rows be an even multiple of the per-page rows is a corner case anyway; if there are 9 or 10 rows you'd have to page again anyway.