. .
.
7. GOMS Model
.
.

 

Back to HCI Lab Home Page

 

 

 

GOMS Model

 

 

GOMS (Goals, Operators, Methods, and Selection rules) is predictive model of human information processing used for task analysis in human computer interaction design. The model was proposed by   Stuart Card, Thomas P. Moran and Allen Newell in 1983. The model  is  used  to  analyze  user’s  physical , cognitive  and   perceptual  interactions  with  computer  while  achieving   a  task  or  a goal  in best possible way.

 

Goals are what users intend to do. Operators are actions they perform to achieve their goals. Methods are operator sequences that accomplish a goal. Multiple methods can exist to accomplish same goal. Selection rules describe when a user will select a method over the other.

 

In Key Stroke Level (KLM) GOMS model  the  physical, cognitive and  perceptual actions  during  a task  is  decomposed  in form  of  fundamental  keystroke sequence. The model specifies time required for each fundamental keystroke. Thus  we  can  predict  the  total  time  of  completing  a  task. Multiple methods can be compared based on the total time to complete a task in order to determine which is the most efficient method for accomplishing the task is.

 

 

Following  example of  basic  GOMS  model is taken from John & Kieras (1996b). It models the task of moving text in a word processor, in the context of editing a manuscript. Note the use of sub goals and selection rules, which do not exist in KLM.

 

GOAL: EDIT-MANUSCRIPT
.     GOAL: EDIT-UNIT-TASK ... repeat until no more unit tasks
.     .     GOAL: ACQUIRE UNIT-TASK
.     .	    .	  GOAL: GET-NEXT-PAGE ... if at end of manuscript page
.     .	    .	  GOAL: GET-FROM-MANUSCRIPT
.     .	    GOAL: EXECUTE-UNIT-TASK ... if a unit task was found
.     .	    .	  GOAL: MODIFY-TEXT
.     .	    .	  .   [select: GOAL: MOVE-TEXT* ...if text is to be moved
.     .	    .	  .       GOAL: DELETE-PHRASE ...if a phrase is to be deleted
.     .	    .	  .       GOAL: INSERT-WORD] ... if a word is to be inserted
.     .	    .	  .     VERIFY-EDIT

*Expansion of MOVE-TEXT goal
GOAL: MOVE-TEXT
.     GOAL: CUT-TEXT
.     .     GOAL: HIGHLIGHT-TEXT
.     .		.	[select**: GOAL: HIGHLIGHT-WORD
.     .		.		   .   MOVE-CURSOR-TO-WORD
.     .		.		   .   DOUBLE-CLICK-MOUSE-BUTTON
.     .		.		   .   VERIFY-HIGHLIGHT
.     .		.	   	   GOAL: HIGHLIGHT-ARBITRARY-TEXT
.     .		.		   .	 MOVE-CURSOR-TO-BEGINNING	1.10
.     .		.		   .	 CLICK-MOUSE-BUTTON		0.20
.     .		.		   .	 MOVE-CURSOR-TO-END		1.10
.     .		.		   .	 SHIFT-CLICK-MOUSE-BUTTON	0.48
.     .		.		   .	 VERIFY-HIGHLIGHT]		1.35
.     .		GOAL: ISSUE-CUT-COMMAND			
.     .		.     MOVE-CURSOR-TO-EDIT-MENU				1.10
.     .		.     PRESS-MOUSE-BUTTON				0.10
.     .		.     MOVE-CURSOR-TO-CUT-ITEM				1.10
.     .		.     VERIFY-HIGHLIGHT					1.35
.     .		.     RELEASE-MOUSE-BUTTON				0.10
.     GOAL: PASTE-TEXT
.     .	    GOAL: POSITION-CURSOR-AT-INSERTION-POINT
.     .		MOVE-CURSOR-TO-INSERTION-POIONT				1.10
.     .		CLICK-MOUSE-BUTTON					0.20
.     .		VERIFY-POSITION						1.35
.     .		GOAL: ISSUE-PASTE-COMMAND
.     .		.     MOVE-CURSOR-TO-EDIT-MENU				1.10
.     .		.     PRESS-MOUSE-BUTTON				0.10
.     .		.     MOVE-MOUSE-TO-PASTE-ITEM				1.10
.     .		.     VERIFY-HIGHLIGHT					1.35
.     .		.     RELEASE-MOUSE-BUTTON				0.10
					TOTAL TIME PREDICTED (SEC)     14.38

Based on the above GOMS analysis, it should take 14.38 seconds to move text.

 


 

   

 

 

 

 


 To proceed  further  click on the OBJECTIVE tab on the top or to exit this experiment  click on HOME  on the top.

 

Cite this Simulator:

.....
..... .....
Copyright @ 2017 Under the NME ICT initiative of MHRD (Licensing Terms)
 Powered by AmritaVirtual Lab Collaborative Platform [ Ver 00.11. ]