I recently had to revise an existing PowerPoint file on usability for a demo, and I’d like to share some of the key points here. I’d place the references in i:\ but at the moment it’s either full or write-protected. Anyway, the presentation describes 5 qualities — the 5Es — of a usable product: Effective, Efficient, Engaging, Error tolerant, and Easy to Learn.
Effective. “Capable of producing an effective result.” This addresses whether the product is useful and helps users achieve goals accurately. If this criterion fails, this would definitely frustrate users more than anything else.
Possible design approaches (as listed in the PowerPoint file):
- provide feedback on all critical actions
- eliminate opportunities for error
- provide sufficient information for user decisions
Efficient. “Being effective without wasting time or effort or expense.” This refers to the speed (with accuracy) with which work can be done using the product. Aside from providing a streamlined work flow, we need to avoid things that can interrupt the users’ work or that could slow them down.
Possible design approaches:
- design navigation for ideal and alternate work flows
- provide shortcuts
- use interaction styles and design widgets that support speed
- minimize extraneous elements on the screen
Engaging. “Attracting or delighting.” This concerns how pleasant, satisfying, or interesting an interface is to use. This means your interface can either encourage the use of the system OR can be a turn-off that makes your system painful to use.
Possible design approaches:
- use clear language and appropriate terminology
- set a helpful tone, with a level of conversation suitable for the users
- structure functions to match users’ tasks
Error Tolerant. This involves how well the product prevents errors and helps users recover from any errors that do occur. No one is perfect so making errors cannot be helped. E.g., you select the wrong option, or click the wrong link, or get into the wrong elevator. If the user makes a mistake, the system must be able to help lead the user back to the correct track. Otherwise, this could lead to a lot of support calls for data amendment.
Possible design approaches:
- transform “errors” into alternate paths
- use controls that aid in accurate selection
- be sure actions are easily reversible
Easy to Learn. This concerns how well the product supports both initial orientation and deeper learning. If you are using a product for the first time, it should be easy enough to figure out how to use it. And if you will only be using it after long intervals, it should not take too much effort to relearn how to use it.
Possible Design Approaches:
- make the interface helpful with minimalist prompts and instructions provided where they are needed
- create “guided” interfaces for difficult or infrequent tasks
Main reference: “Balancing the 5Es: Usability”, Cutter IT Journal, Whitney Quesenbery, 2004
