Boxes And Arrows : The Design Behind the Design

Article Idea:

Measuring based on Fitts' Law

suggested by Alok Jain on 2006/04/11

Very simply speaking Fitts’ law is Big targets at close distance are acquired faster than small targets at long range.

The importance inspite of its simplicity has fascinated me for long time, so I went ahead and did a small evaluation. Am interested to hear if others have applied such evaluation in their work:

Evaluation:

Why I chose email interface? Several reasons are there but here are a couple:
a) Its one of the most commonly used application
b) Base interaction design has been standardized over a period of time

Tasks Flow I considered (Purposefully kept simple):
1. Enter URL
2. Sign In
3. Access Inbox
3a. Composing New email—> Attach a file
3b. View first email

Evaluation Data:

Average distance traveled by user’s mouse:

Yahoo: 7.26 Units
Gmail: 5.91 Units
Ureach: 7.07 Units

Comparitive Chart:

(“Inbox” Task for Gmail is Zero as sign-in directly takes to inbox and explicit clicking on Inbox is not requried in Gmail)

Average Width of Target:
Yahoo: 0.95 Units
Gmail: 0.98 Units
Ureach: 0.85 Units

Comparitive Chart:

Average Height of Target:
Yahoo: 0.26 Units
Gmail: 0.20 Units
Ureach: 0.22 Units

Comparitive Chart:

Also considering the direction – # of times user needs to move the mouse from right to left:

Yahoo – 40%
Gmail – 50%
Ureach – 40%

This is quick and dirty exploration, but I believe, it can be enhanced and applied to critical aspects of interface.