External and Task Analyses. Overview. Traditional Software Development. SMD157 Human-Computer Interaction Fall 2005

Transcription

1 INSTITUTIONEN FÖR SYSTEMTEKNIK LULEÅ TEKNISKA UNIVERSITET External and Task Analyses SMD157 Human-Computer Interaction Fall 2005 Nov-4-05 SMD157, External & Task Analyses 1 L Overview Traditional software development External analysis Example external analysis Task analysis Example task analysis Nov-4-05 SMD157, External & Task Analyses 2 L INSTITUTIONEN FÖR SYSTEMTEKNIK LULEÅ TEKNISKA UNIVERSITET Traditional Software Development Nov-4-05 SMD157, External & Task Analyses 3 L 1

2 The Software Life Cycle: Six Phases Specification Implementation Requirements Definition Testing Maintenance Installation Nov-4-05 SMD157, External & Task Analyses 4 L Traditional Design Methods Focus on the technical aspects of the system - Database used, - Data stored, - Computer hardware requirements,... Focus on the quality requirements - Security provided, - Relative freedom from errors, - Commented code,... Nov-4-05 SMD157, External & Task Analyses 5 L Traditional Development Methods Linear Process - Write specifications - Build system - Test against specifications - Deploy Result Unusable Systems Why? - The non-technical is very important. - Remember the Vincennes Nov-4-05 SMD157, External & Task Analyses 6 L 2

3 INSTITUTIONEN FÖR SYSTEMTEKNIK LULEÅ TEKNISKA UNIVERSITET External Analysis Nov-4-05 SMD157, External & Task Analyses 7 L External Analysis Used to collect the non-technical requirements Characterizes - The users - Their work - The work environment Goals - Understand external (outside the system) factors - Identify system services - Identify usability goals Nov-4-05 SMD157, External & Task Analyses 8 L Characterizing the User User characteristics - Age, Gender, Physical abilities, Education, Goals - Cultural or ethnic background, Training, Motivation Usage profiles - Novice or first-time users - Knowledgeable intermittent users - Expert frequent users - Division of labor + Different assignments or always the same? Nov-4-05 SMD157, External & Task Analyses 9 L 3

4 Creating Personae, Fictional Users It is easier to design a product for someone. Design for the user! AND, you are not the user! Create fictional users A Fictional user is called a Persona - Detailed description, age, sex, education, - Include Goals - Write them up! Nov-4-05 SMD157, External & Task Analyses 10 L Personae There are usually several personae Choose one as the principle or head persona - Whose goals are the most important? - Whose goals subsume the goals of other personae? - Who must be satisfied for the system to succeed? Focus on the head persona Nov-4-05 SMD157, External & Task Analyses 11 L A Note on Goals User goals and work goals are not the same. User goals: - Want to escape boredom - Don t want to be made to feel stupid - Don t want to work too hard - Want to get the job done, not fight with the computer - Want to get done and do interesting stuff, like ski! Work goals: - Want workers to accomplish the maximum - Want to do it cheaply - Want workers to accomplish a set of tasks (e.g., sell insurance) - Hereafter, work goals will be called tasks. The system cannot violate user goals and must allow work goals to be accomplished! Nov-4-05 SMD157, External & Task Analyses 12 L 4

5 Characterizing the Work What is done? How? - Pay attention to exceptions and special situations! How does information flow? - Steps, sequences, and parallel tasks Is work: - Performed by a group? - Coordinated with others? Current tools Current artifacts (reports, documents,...) Nov-4-05 SMD157, External & Task Analyses 13 L Example, Air Traffic Control The British Aviation Authority decide to upgrade the air traffic control system in the late 1980 s. A new system know as RD3 was developed. - Added extra display capabilities - Enabled controllers to manage a sector by themselves The system was not accepted Why was the less technically advanced solution preferred? Nov-4-05 SMD157, External & Task Analyses 14 L Air Traffic Control, the Answers RD3 ignored current work structure: - Controllers managed a sector with the aid of assistants who: + Managed the information about flights on paper strips + Helped identify potential conflicts - They were supervised by a chief who: + Supervised several sectors + Smoothed the handoff + Looked for conflicts between sectors + Handled unusual situations Nov-4-05 SMD157, External & Task Analyses 15 L 5

6 Air Traffic Control, the Answers RD3: - Had more complex displays - Made it impossible for the chief to handle unusual situations - Increased the responsibilities of the individual controller - Had properties that lead to distrust Nov-4-05 SMD157, External & Task Analyses 16 L Example, a Crime Statistics Reporting System Was deployed in Northern England primarily to provide management reports about crime trends. - Used to plan manpower shifts - Used to asses the results of these shifts Turned out to have an unexpected benefit - Detectives used it to help clear up crimes - Even though the UI was awful Nov-4-05 SMD157, External & Task Analyses 17 L Environment Can affect system use: - Noise is unacceptable in a library - Background noise can render speech systems useless. - Audible warning signals can be vital in a visually crowded environment Check - What does the work area look like? - Are some tasks allocated special areas? - Where are the users? Nov-4-05 SMD157, External & Task Analyses 18 L 6

7 Environment Other factors: - Language - Domain concepts - Domain objects Nov-4-05 SMD157, External & Task Analyses 19 L Environment, Example Underwater PC Problem: - Not waterproofing - Interaction Why: - One hand free - Noise disturbs voice recognition - Track balls require flat surface Solution - Cord keyboard in grip Nov-4-05 SMD157, External & Task Analyses 20 L Methods for External Analysis Interviews Passive observation Active participation Analysis of the results Nov-4-05 SMD157, External & Task Analyses 21 L 7

8 Interviews Prepare general questions in advance. Let the interviewee talk. Start with having them describe familiar, routine things Be alert for special situations. - Systems must handle exceptions - Collections example Usually audio recorded, but ask when the appointment is made. Nov-4-05 SMD157, External & Task Analyses 22 L Semi-Structured Questions What do you do? Why do you do it? How do you do it? What are the preconditions? What is the result? What errors can occur? How do you fix them? Obtains the user s goal. Gets the method. Gets subtasks, use recursively. Finds out the outside influences. Examines product or purpose. Capture the errors. Capture error correction. Nov-4-05 SMD157, External & Task Analyses 23 L Things to Watch People will often tell you the official story. What users say they prefer and what they actually prefer when the system is implemented are often different. - Evaluation with out the experience is dubious People away from the work environment and the task don t remember much or accurately. - Interview in the context of the task. (Contextual Inquiry) Nov-4-05 SMD157, External & Task Analyses 24 L 8

9 Passive and Active Observation Passive - Video observations - Taking notes from the sidelines - Beware of the Hawthorne effect! Active - Become a member of the work group - Participate in the work while taking note. Participatory design Nov-4-05 SMD157, External & Task Analyses 25 L Analysis Create transcripts Assemble and collate information Form theories about the work Test them against the data Nov-4-05 SMD157, External & Task Analyses 26 L Output Description of personae, head persona Specification of system services - Broad description of what the system should do, not detailed functions. - Limit the system scope and the implementation problem Usability goals Scenarios - Stories of personae using the system - Can be recorded as a UML use case or a storyboard Nov-4-05 SMD157, External & Task Analyses 27 L 9

10 Usability Goals Speed of performance Error incidence Ease of error recovery Magnitude of task to learn the system Ease of retention of operating knowledge Customizability to the user way of working Support for reorganization of activities User satisfaction Nov-4-05 SMD157, External & Task Analyses 28 L Storyboard Example 1. Håkan works as an optimization expert at Ericsson. One day, he s called to a client s site to s olve some complex problems with network performance. As usual, it s a long flight to g et there In the morning of the first day, Håkan gets an introduction to the problem areas by the client s own network optimizers. 3. Customer complaints tell Håkan where to look, but in order to pinpoint the p roblematic cell(s), he and t he other optimizers take a TEMS, mobile test instrument, and drive in the area. abbreviated Nov-4-05 SMD157, External & Task Analyses 29 L INSTITUTIONEN FÖR SYSTEMTEKNIK LULEÅ TEKNISKA UNIVERSITET Example External Analysis PDA Controller for Copiers Nov-4-05 SMD157, External & Task Analyses 30 L 10

11 Example Every teacher at LTU is to get a PDA with a wireless connection The PDA will be used operate the copy machines. Specifically: - Accounting by activity will be entered - The copier will be programmed via the PDA instead of the control panel Design a PDA program to accomplish the goals. Nov-4-05 SMD157, External & Task Analyses 31 L Personae The main persona is a teacher - Håkan - Swedish, male, 40ish, well educated, doesn t have time to fiddle with technology, experienced user of basic office programs - Main goal is to get the teaching done, not fiddle with the copier Other personae - Secretaries, administrators, copier service personal Nov-4-05 SMD157, External & Task Analyses 32 L Example, Use of the Copier (by a Teacher) What do you do? - Make single copies of individual documents. - Create two-sided copies of one-sided documents or articles from books. - Make one sided copies of articles as masters for course compendiums - Make compendiums. Why? - I need an extra copy. - To read on the plane, because they are lighter and less bulky. - Single sheet feed, 1-sided to 2- sided is the fastest mode to produce the lest bulky 2-sided copies. - In a hurry and can t send it out. Nov-4-05 SMD157, External & Task Analyses 33 L 11

12 Example How do you do it? - From a book for compendium masters + Set up the copier for input from a book + Copy each pair of pages that has at least part of the article + Check the copies to see that they are readable + Throw away pages that aren t part of the article. - For 2-sided copies + as above, plus + run the one-sided pages through on 1->2 copying Nov-4-05 SMD157, External & Task Analyses 34 L Example Preconditions - Marking the article - Copier free, Results - A stapled copy of the article in A4 format Nov-4-05 SMD157, External & Task Analyses 35 L Example Errors - Forget to set staple mode - Bad one-side copies - Paper jam - Missing pages from the article Corrections - Hand staple - Redo - Clear and redo - Copy them and sort output Nov-4-05 SMD157, External & Task Analyses 36 L 12

13 One Might also Ask How Often? Make single copies of individual documents. Create two-sided copies of one-sided documents or articles from books. Make one sided copies of articles as masters for course compendiums Often, half of the time Frequently Once or twice per term, but there are many articles. Make compendiums. Only, if I must. Nov-4-05 SMD157, External & Task Analyses 37 L INSTITUTIONEN FÖR SYSTEMTEKNIK LULEÅ TEKNISKA UNIVERSITET Task Analysis Nov-4-05 SMD157, External & Task Analyses 38 L Task Analysis Organization of user interaction with the system into: - Tasks (work goals) - Methods Constructs a model of user/system interaction - Usually hierarchically composed - Usually emphasizes sequence of operation Nov-4-05 SMD157, External & Task Analyses 39 L 13

14 Task Analysis A description of the tasks for each class of user (personae) is required. How to do these tasks becomes the highest-level set of user tasks. Refine the task analysis until you have a description of what each user must know to perform each task. You must have this information available when the user needs it. This will influence your display designs. Nov-4-05 SMD157, External & Task Analyses 40 L Typical Task Input Transformation Output Nov-4-05 SMD157, External & Task Analyses 41 L Questions to Answer About the Task Inputs - What information is needed? - What are the characteristics of the information sources? (reliable?, in needed form?) - What is the availability of the information? - Who or what initiates the task? Outputs - What are the performance criteria - What happens to the output? - How does that task performer get feedback about task performance? Nov-4-05 SMD157, External & Task Analyses 42 L 14

15 Questions to Answer About the Task The process of transformation - What is the nature of decision making - What strategies exist for decision making - What skills are needed. - What interruptions are likely to occur? When? Task composition - How often is it done and when? - Is it dependant on other tasks? - What is normal/abnormal workload? - What control does the task performer have over workload? Nov-4-05 SMD157, External & Task Analyses 43 L Use fork/join to represent parallel or unordered activities An activity in a fork/join is optional if labeled with a [condition] An activity may contain a more detailed activity description, mark with an (*) Notation for Recording, UML Activity Diagrams [condition] Activity branch merge [else] Activity end Nov-4-05 SMD157, External & Task Analyses 44 L start Activity Concurrent Activity fork join INSTITUTIONEN FÖR SYSTEMTEKNIK LULEÅ TEKNISKA UNIVERSITET Example Task Analysis PDA Controller for Copiers Nov-4-05 SMD157, External & Task Analyses 45 L 15

16 Example, the Copier Control User goals become the top level tasks. From the question What do you do? - Make single copies of individual documents. - Create two-sided copies of one-sided documents or articles from books. - Make one-sided copies of articles as masters for course compendiums - Make compendiums. Nov-4-05 SMD157, External & Task Analyses 46 L Refine the Top-Level Remember, exact duplication is most frequent. Note, making compendium masters is a subset of converting book articles to two-sided copies for reading Note, making compendiums and copying one-sided articles to two sides are the same task. New subtasks - Make one-sided masters from books. - Make two-sided copies from one-sided originals Nov-4-05 SMD157, External & Task Analyses 47 L Top-Level Activity Diagram [compendium masters] 1-Sided Masters from Books* [make compendium, 2-sided article] 2-Sided Copies from Paper* [2-Sided from Books] 1-Sided Masters from Books* Single Copies* 2-Sided Copies from Paper* Nov-4-05 SMD157, External & Task Analyses 48 L 16

17 One-Sided Masters Setup Copier* Copy Relevant Page Pairs Cull Unwanted Pages Check Pages Nov-4-05 SMD157, External & Task Analyses 49 L Things to Consider Are intermediate paper copies (compendium masters) necessary or an artifact of the existing method? Would the user like to save setups? Should the simple duplicate function be easiest to access? What else can be done with a PDA to simplify the task? Nov-4-05 SMD157, External & Task Analyses 50 L Summary Traditional software development External analysis Task analysis Nov-4-05 SMD157, External & Task Analyses 51 L 17

18 Questions? Nov-4-05 SMD157, External & Task Analyses 52 L 18