GOMS Model on Instructional Design Prepared By: RekahVeloo Date:16th Aug 2010 Lecture: Dr. BalakrishnanMuniandy Course Code: QIM 501E
Abstract • Definition: Instruction Design • A systematic development of instructional specifications using learning and instructional theory to ensure the quality of instruction. It is the entire process of analysis of learning needs and goals and the development of a delivery system to meet those needs.
Abstract • Traditional Approach: • A subject is observed in order to record the different task, actions and time is needed to perform a specific task. • Result will use to define metrics and to optimize the workflow. • Modern Approach: • Computer as a mean to deliver instruction, the task analysis has been redesigned in order to consider human computer factors.
Overview :GOMS Model • Developed in 1983 by: • Stuart Card, Thomas P. Moran & Allen Newell • Description of the Model: • Kind of specialized human information processor model for human computer interaction observation and predict user behavior. Typically used by software designers. • The knowledge and skills that a user must have in order to carry out task on a device or system. (Kieras, 1988) • It is representation of “how to do it” knowledge that is required by a system in order to get intended task completed. • Believed applied information processing psychology should be based on task analysis, calculation and approximation.
Biography Stuart Card Allen Newell Thomas P. Moran
Principles • Goals • Something that the person wants to accomplish. Can be high level (e.g. WRITE-PAPER) to low level (e.g. DELETE CHARACTER) • High level goals are decomposable into sub goals, and are arranged hierarchically. • Operator • Basic perceptual, cognitive, or motor actions used to accomplish goals, or actions that the software allows user to make (e.g. PRESS-ENTER-KEY or CLICK-MOUSE). • Not decomposable: they are atomic elements in the GOMS model. • It is generally assumed that each operator requires a fixed amount of time for the user to execute, and that this time interval is independent of context (e.g. CLICK-MOUSE button takes 0.20 seconds to execute).
Principles • Methods • Procedures (sequences) of sub goals and operators that can accomplish the goals. • E.g: one method to accomplish the goal DELETE-WORD in the “Emacs” text editor would be to MOVE-MOUSE to the beginning of the word, and PRESS-ALT-D-KEY-COMBINATION (the use-mouse-delete-word method). Another method to accomplish the same goal could involve using the arrow keys to reach the beginning of the word (the use-arrows-delete-word method). • Selection Rules • Personal rules users follow in deciding what method to use in a circumstance. • E.g:"if the word to be deleted is less than 3 lines away from the current cursor location, then use the use-arrows-delete-word-method, else use the use-mouse-delete-word method"
Scope & Application Provides the designer with a model of a user’s behavior while performing well known task, whereby these models can be used for a variety of purposes:
GOMS Epistemology • Learning involve knowledge acquisition & it is important to recognize the different sources of knowledge and the epistemology involve. • When a person use a system or device, the knowledge is obtained through a sensory experience. Whereby knowledge come from outside the learner and its known through the continuous use of the tool. • In GOMS, the interaction between a computer and human being used 3 different stages on memory: • perceptual system • the motor system • the cognitive system
Model Human Processor (MHP) Receives inputs from the different devices such monitor & speakers Already familiar with the system-> retrieves information from long term memory Apply the correct methods according to rules
Instructional Design Process • Choose user’s goals • Objective: Determine what the learners needs to know / accomplish after the instruction. Provide the inputs for training materials which used to analyze the learn ability factors of the system & provide feedback to the system designers to consider a redesign on the user interface. • Perform the following recursive procedures: • Draft a method to accomplish each goal by simply listing the steps as general or high-level as possible for the current level of analysis and by passing complex psychological process. • Check each step and rewrite as needed for conformance to guidelines. (includes checking on method detail & length, consistency in assumptions about users skill level, and that each high-level operator corresponds to a natural goal.)
Instructional Design Process • If needed, go to lower level of analysis by changing the higher-level operators, and then provide methods for the corresponding goals. At the bottom all operators are primitives. If they are not , then need to decide whether to provide a methods for performing it. • Document & check the analysis • List all primitive external operators used, analyst-defined operators, assumptions, & judgment call made. • Should check the accuracy if the model by executing the methods as carefully as possible. Make sure that the methods procedure the outcomes on the system. • Check sensitivity of judgment calls and assumptions made during the analysis.
GOMS Variants • Several variations of the GOMS model have been proposed to address issues with the original model.
Keystroke-Level Model (KLM) • Simplest variant of GOMS • KLM model applications : • mouse-driven text editors. • workstations for directory-assistance telephone operators. • space operations database systems. • CAD/CAM software. • This model is unsuited to analyzing more abstract tasks such as EDIT-MANUSCRIPT, which involve conditionals and decomposition into sub goals.
Example: KLM • Describe the task using the following operators • K: keystroke, mouse button push • P: point with pointing device • D: move mouse to draw line • H: move hands to keyboard or mouse • M: mental preparation for an operation • R: system response time • Tasks split into two phases • Acquisition of task - user builds mental representative. • Execution of task - using system facilities
Example: KLM • Text editing task of searching a Microsoft Word document for all occurrences of a four-letter word, and replacing it with another four-letter word • According to this KLM model, it takes 10.2 seconds to accomplish this task.
CMN-GOMS • The original GOMS model proposed by Card, Morn and Newell (1983) • Builds on KLM by adding sub goals and selection rules. • This technique requires a strict goal-method-operation-selection rules structure. • Can predict operator sequence as well as execution time. • Can be represented in program form, making it amenable to analysis as well as execution. • CMN-GOMS Model application: • model word processors (Card et. al, 1983) • CAD system for ergonomic design(John & Kieras, 1996) • Sun Microsystem's web page.
EXAMPLE: CMN-GOMS GOAL: DELETE-FILE . GOAL: SELECT-FILE . . [select: GOAL: KEYBOARD-TAB-METHOD . . GOAL: MOUSE-METHOD] . . VERIFY-SELECTION . GOAL: ISSUE-DELETE-COMMAND . . [select*: GOAL: KEYBOARD-DELETE-METHOD . . . PRESS-DELETE . . . GOAL: CONFIRM-DELETE . . GOAL: DROP-DOWN-MENU-METHOD . . . MOVE-MOUSE-OVER-FILE-ICON . . . CLICK-RIGHT-MOUSE-BUTTON . . . LOCATE-DELETE-COMMAND . . . MOVE-MOUSE-TO-DELETE-COMMAND . . . CLICK-LEFT-MOUSE-BUTTON . . . GOAL: CONFIRM-DELETE . . GOAL: DRAG-AND-DROP-METHOD . . . MOVE-MOUSE-OVER-FILE-ICON . . . PRESS-LEFT-MOUSE-BUTTON . . . LOCATE-RECYCLING-BIN . . . MOVE-MOUSE-TO-RECYCLING-BIN . . . RELEASE-LEFT-MOUSE-BUTTON] *Selection rule for GOAL: ISSUE-DELETE-COMMAND If hands are on keyboard, use KEYBOARD-DELETE-METHOD, else if Recycle bin is visible, use DRAG-AND-DROP-METHOD, else use DROP-DOWN-MENU-METHOD
NGOMSL • Natural GOMS Language • Builds based on CMN-GOMS by providing a natural-language notion for representing GOMS models. • Methods are represented in terms of an underlying cognitive theory known as cognitive complexity theory, or CCT. • This cognitive theory allows NGOMSL to incorporate internal operators such as manipulating working memory information or setting up sub goals. • NGOMSL also can be used to estimate the time required to learn how to achieve tasks.
Example: NGOMSL Goal: Move a file into a subfolder in Windows XPMethod for accomplishing goal of moving a file using the drag and drop option: Step 1: Locate the icon of the source file on the screen Step 2: Move mouse over the icon of the source file Step 3: Press and keep holding the left mouse button Step 4: Locate the icon of the destination folder on the screen Step 5: Move mouse over the icon of the destination folder Step 6: Release left mouse button Step 7: Return with goal accomplished Kieras, David (1996). "A Guide to GOMS Model Usability Evaluation using NGOMSL
Example: NGOMSL Method for accomplishing goal of moving a file using the cut and paste option: Step 1: Recall that the first command is called "cut" Step 2: Recall that the command "cut" is in the right click menu Step 3: Locate the icon of the source file on the screen Step 4: Accomplish the goal of selecting and executing the "cut" command Step 5: Recall that the next command is called "paste" Step 6: Recall that the command "paste" is in the right click menu Step 7: Locate the icon of the destination folder on the screen Step 8: Double click with left mouse button Step 9: Locate empty spot on screen Step 10: Move mouse to the empty spot Step 11: Accomplish the goal of selecting and executing the "paste" command Step 12: Return with goal accomplished • Selection rule set for goal: Move a file into a subfolder in Windows XP • If custom icon arrangement is used Then accomplish goal: cutting-and-pasting. • If no custom icon arrangement is used Then accomplish goal: drag-and-drop. • Return with goal accomplished.
CPM-GOMS • Cognitive-Perceptual-Motor GOMS (CPM-GOMS) • builds on previous GOMS models by assumed that perceptual, cognitive and motor operators can be performed in parallel. • It employs a schedule chart (also known as a PERT chart) to represent operators and dependencies between operators.
Example: CPM-GOMS CPM-GOMS model, John & Kieras (1996b.)
Advantage of GOMS • The learn ability factors is measured based on the time or effort that it takes to a user to get used to the system and its operation. • Includes how easy to remember some operational steps in order o complete a task. • Analysis provide quantitative and qualitative information. • Training programs and help systems can be built based on the description of the knowledge needed to perform a task, producing a task oriented document.
Conclusion • GOMS is a model/technique used to analyze the human computer interaction process. • It uses not only discover the cognitive model of an user interacting with a system but it also provides the mechanism to estimate learning time, time on task and probability of errors. • It also demonstrates that the information processing system plays an important role on the human computer interaction.
Reference • Website • http://www.cs.umd.edu/class/fall2002/cmsc838s/tichi/goms.html • http://www.etutors-portal.net/Partners/eTutors-TRANSNET/OLD%20Language%20Folders/Romanian%20Language%20Folder/f1/Folder.2004-02-26.4226/LearningTheories.doc • http://tip.psychology.org/card.html • http://www.cc.gatech.edu/computing/classes/cs6751_98_fall/handouts/GOMS-Kieras.html • http://books.google.com.my/books?id=zOy0duJzDjQC&pg=PA111&lpg=PA111&dq=goms+instructional+design&source=bl&ots=BkH0rG_QfP&sig=BbcuVxlyRtGx0K2qoIYHZ3GQ8xU&hl=en&ei=OedlTPLoMsiecaPjgbIK&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBgQ6AEwAA#v=onepage&q=goms%20instructional%20design&f=false • Article: • GOMS Theory and its use on the Instructional Design Process, Maricel Medina-Mora.