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Task Analysis Analyzing and describing how people do their jobs/work
-> Go to their environment Examine users’ tasks to better understand what they need from interface and how they will use it Fall 2002 CS/PSY 6750
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Components Three key components to include in discussing how people work Activities Artifacts Relations Don’t just focus on computer system artifacts and interactions Study related processes and objects in the environment that people may use and involve Example: office env---papers, whiteboards, etc. Fall 2002 CS/PSY 6750
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Task Analysis Focus Focus on observable behaviors
What are the practices, methods, steps, objects, …, used? Observe users, what they do, less so how they do it Not on internal cognitive state of user (more on that next week) Fall 2002 CS/PSY 6750
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Input & Output Gather data: Represent Data: Documentation Interviews
Observation Surveys/questionnaires Automatic data recording/tracking Represent Data: Lists, outlines, matrices Narratives Hierarchies & Networks Flow charts Fall 2002 CS/PSY 6750
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Data to be Gathered Information about users Description of environment
Where the tasks will be performed Major goals of the job What will result in a successful end state? User preferences & needs Before they even start: coffee, pen, notebook, log sheets… Fall 2002 CS/PSY 6750
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Data to be Gathered … Tasks & Subtasks:
Physical Cognitive Communication Conditions under which these tasks are done Results/outcomes of tasks Requirements to perform task: Information Communication with others Equipment Must include Should include Could include Exclude Fall 2002 CS/PSY 6750
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Data Gathering Tools: Docs
Documentation Often contains description of how the tasks should be done (rather than how they are currently being done) Standards Manuals Histories Best Practices Domain Expert Description Expert describes how process should work, how tasks should be done “Knowledge-based” discovery Fall 2002 CS/PSY 6750
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DGT: Interviews Interviews: Structured Unstructured Semi-structured
Efficient Require training Unstructured Inefficient No training Semi-structured Good balance Often appropriate Fall 2002 CS/PSY 6750
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Semi-structured Interviews
Predetermine data of interest Plan for effective question types How do you perform task x? Why do you perform task x? Under what conditions do you perform task x? What do you do before you perfom…? What information do you need to…? Who do you need to communicate with to…? What do you use to…? What happens after you…? What is the result or consequence of…? What is the result or consequence of NOT…? See: Gordon & Gill, 1992; Graesser, Lang, & Elofson, 1987 Fall 2002 CS/PSY 6750
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DGT: Observation Observation In situ, watch users do what they do
Record with videotape To watch later, or again Take lots of notes, sketches May require coding the video later Focus on specific task-relevant behaviors in notes, but later convert to abstract subtasks Fall 2002 CS/PSY 6750
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DGT: Questions Questions & Answers Questionnaires
Exploratory vs. confirmatory Open-ended vs. categorical (exhaustive) What do you need to perform..? (list) Which of the following is most important to perform…? (select) If you ask it, use it. If you won’t/can’t use it, don’t ask it. Fall 2002 CS/PSY 6750
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DGT: Think-aloud Questions & Answers, cont’d… Think-aloud protocol
Person talks about what they are doing, while they are doing it (or just before or after) Observer can ask probe questions Why did you just do that? Note: Probe questions affect performance, as does thinking aloud. Fall 2002 CS/PSY 6750
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DGT: Logging Automatic tracking Keystroke/mouse click monitoring
Timers Logs Physical location/movement trackers Cell phones Aware Home Fall 2002 CS/PSY 6750
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Representing Data: Outlines
Lists, outlines, matrices Use expanding/collapsing outline tool Add detail progressively Know in advance how much detail is enough Can add linked outlines for specific subtasks Good for sequential tasks Does not support parallel tasks well Does not support branching well Example, next slide Fall 2002 CS/PSY 6750
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Task Outline Using a lawnmower to cut grass Step 1. Examine lawn
Make sure grass is dry Look for objects laying in the grass Step 2. Inspect lawnmower Check components for tightness Check that grass bag handle is securely fastened to the grass bag support Make sure grass bag connector is securely fastened to bag adaptor Make sure that deck cover is in place Check for any loose parts (such as oil caps) Check to make sure blade is attached securely Check engine oil level Remove oil fill cap and dipstick Wipe dipstick Replace dipstick completely in lawnmower Remove dipstick Check that oil is past the level line on dipstick …
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RD: Narratives Narratives Describe tasks in sentences
Often expanded version of list or outline More effective for communicating general idea of task Not effective for details Not effective for branching tasks Not effective for parallel tasks Fall 2002 CS/PSY 6750
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RD: Hierarchies Hierarchical Task Analysis (HTA)
Graphical notation & decomposition of tasks Tasks as sets of actions Tasks organized into plans Clusters of subtasks with a preferred order and prerequisite conditions Fall 2002 CS/PSY 6750
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HTA
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Example Task Clusters Fixed sequence Optional tasks Waiting events
Cycles Time-sharing Discretionary Fall 2002 CS/PSY 6750
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RD: Networks Network / Entity-Relationship Diagrams
Objects/people with links to related objects Stress relationship between objects and actions Links described functionally and in terms of strength Task: Develop design for final project objects - pens, paper, drawing tools, etc. actors - Mary, Bob, Sally composite objects - the “team” Fall 2002 CS/PSY 6750
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Methodology Often list attributes, actions of objects
Object: pen simple Attribute: color: red writing: on/off Object: Mary actor Actions: M1: make a sketch M2: organize meeting Fall 2002 CS/PSY 6750
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RD: Flow Charts Flow Chart of Task Steps
Combines Entity-relationship (network) with sequential flow, branching, parallel tasks. Includes actions, decisions, logic, by all elements of the system Abstracted Mature, well-known, good tools Fall 2002 CS/PSY 6750
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Flow Chart Start Continue? Document Manual Operation Y N Input Display
End Fall 2002 CS/PSY 6750
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Summary of Task Analysis
Determine the data you need Gather it using various appropriate methods and techniques Represent the tasks and subtasks, plus other related information Use this data to improve design Note: Be efficient! Fall 2002 CS/PSY 6750
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