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Task Analysis

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. Components. Three key components to include in discussing how people work Activities Artifacts

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Task Analysis

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  1. 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 CS/PSY 6750

  2. 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. CS/PSY 6750

  3. 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 CS/PSY 6750

  4. Input & Output • Gather data: • Documentation • Interviews • Observation • Surveys/questionnaires • Automatic data recording/tracking • Represent Data: • Lists, outlines, matrices • Narratives • Hierarchies & Networks • Flow charts CS/PSY 6750

  5. 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… CS/PSY 6750

  6. 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 CS/PSY 6750

  7. 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 CS/PSY 6750

  8. DGT: Interviews • Interviews: • Structured • Efficient • Require training • Unstructured • Inefficient • No training • Semi-structured • Good balance • Often appropriate CS/PSY 6750

  9. 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 CS/PSY 6750

  10. 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 CS/PSY 6750

  11. 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. CS/PSY 6750

  12. 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. CS/PSY 6750

  13. DGT: Logging • Automatic tracking • Keystroke/mouse click monitoring • Timers • Logs • Physical location/movement trackers • Cell phones • Aware Home CS/PSY 6750

  14. 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 CS/PSY 6750

  15. 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 …

  16. 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 CS/PSY 6750

  17. 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 CS/PSY 6750

  18. HTA

  19. Example Task Clusters • Fixed sequence • Optional tasks • Waiting events • Cycles • Time-sharing • Discretionary CS/PSY 6750

  20. 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” CS/PSY 6750

  21. 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 CS/PSY 6750

  22. 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 CS/PSY 6750

  23. Flow Chart Start Continue? Document Manual Operation Y Input N Display End CS/PSY 6750

  24. 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! CS/PSY 6750

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