In this GOMS dissection of the task, it is shown that the two versions have very similar completion times. In fact, they are shown to be virtually identical when the new rule verification alert box (Screen 3 below) is included. The reason for this is that the method of GOMS that is being used here is very basic. There are other methods of GOMS (NGOMSL, CPM-GOMS), which might show the differences but these complex analysis techniques are beyond the scope of this paper.
|
action |
analysis & discussion |
|
Screen 1 - click on ‘Add Rule’ - system response |
Click
button :: MH MP K = 4.4 System
response :: R |
|
Screen 2 - click action checkbox (move) - click file location dropdown - select folder - click ‘ok’ - system response |
Click
checkbox :: MP K = 2.65 Click
dropdown :: MP K = 2.65 Click
folder :: MP K = 2.65 Highlight
text :: MP KP = 1.35+1.1+0.2+1.35+0.2 = 5.2 Change
text :: (MH MK (one
letter)) or (MH MKKKKKKKKK (type)) =
(1.35+0.4+1.35+0.2) or (1.35+0.4+1.35+(9*.2)) = 3.3 or 4.9 Click
button :: MH MP K = 4.4 System
response :: R |
|
Screen 3 (optional) - system response |
Optional because in previous step, user actions are always
displayed so user is more likely to catch own errors Click
button :: MP K = 2.65 System
response :: R |
|
Total |
27.9 or 29.5 (or with
verification, 30.55 or 32.15) |
While they obviously don't make a significant impact in this simple quantitative view, the improvements in this second version of the task improvement are noteworthy. A more qualitative approach to analysis helps to expose some of these phantom changes. next>>
screen 0a - 0b - 1 - 2 - 3 - 4a - 4b - 5 - 6 - 7a - 7b - GOMS - heuristics
screen 1a - 1b - 2a - 2b - 2c - 3a - GOMS - heuristics
screen 1a - 1b - 2a - 2b - 2c - GOMS - heuristics