How should I implement a 'recently used' list in a dropdown function?

Question

I'm building a complex web app that has a number of places where the user will need to select things from dropdowns. The dropdown lists can be quite long. We are already using the Select2 library to allow for text searching within the dropdowns, but we've received feedback from multiple users that they'd like quick access to recently-used items.

What's the best way to implement a recently-used list?

I can see a few ways forward:

1. Sort the entire list by recency first, alpha second (that is: most-recent at top and all items without recency data below, sort alphabetically).
2. Have a 'Recently used' section at the top with the x most-recently-used items (3? 5? 10?) and an 'All' section below with everything on the list.
3. Have a 'Recently used' section at the top with x most-recently-used items and a section below that has all the rest of the items (all items minus the recently used ones).

I can also sort instead by frequency of use instead of recency. I have a sense that the specific dynamics of our system will determine whether frequency or recency is better, but I'm not sure how to diagnose that without a lot of user data, something we won't get until we fully launch later next year.

Questions:

• Is there any good research on recently used lists of this type?
• What style of list works better for users?
• How can I figure out if frequency or recency is a better approach?

Answer 1

Option 2 is a better idea.

"Have a 'Recently used' section at the top with the x most-recently-used items (3? 5? 10?) and an 'All' section below with everything on the list."

In terms of your 'recency or frequency' question, it all depends on what you are holding in the list. For example, if you have data which the user is unlikely to select differently each time, go for frequency. If you have data which the user will change over time, but select the same items for a short while, use recency.

Maybe another idea could be to allow a user to have favourites at the top of the list? They could click a star on the elements they would prefer to have at the top.

I have found some interesting articles on drop down boxes which are linked to below:

Redesigning the country selector

A better way to design a drop down field

Answer 2

I feel from a user's standpoint that I very much appreciate a list that auto completes as I type. I don't mean just the first letter, but each letter drills you down farther. In my experience it is the quickest way to get to am item bar none. It is also very rare and I wish more programmers would do it or use tools that do it for them if they aren't into complex coding. I at least expect the first letter capability in every list I encounter and I always try it to my somewhat often disappointment.