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HCI Research Project. Research Paradigms. Theoretical ( in the style of mathematics ) Mathematical deduction Simulation Analysis of algorithms Experimental ( in the style of psychology ) Hypotheses checked with controlled experimentation. Theoretical Research. The researcher:
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Research Paradigms • Theoretical (in the style of mathematics) • Mathematical deduction • Simulation • Analysis of algorithms • Experimental (in the style of psychology) • Hypotheses checked with controlled experimentation
Theoretical Research The researcher: • Checks many examples • Conjectures a result in the form of a theorem • Constructs the proof of the theorem from known results
Experimental Research The researcher: • Poses hypotheses • Extensive background reading • Appropriate theoretical model • Conducts controlled experiment • Performs statistical analysis of data • Draws conclusions
Sample Research Questions • Why don’t typical users invoke advanced search strategies? • What is the preferred method of making a choice from a lengthy list? Note behavior of scroll bar, key index • What is the best semantics for the Tab key operating on a Web form? • What is the best shopping cart checkout design?
Sample Research Questions (2) • What is the task analysis of purchasing an airplane ticket? • How should information scent be shown on search reports? • How should editing capabilities for a contact list be implemented for a telephone interface? • Does providing a site map improve web site navigation?
Questions to Hypotheses • Key is measurability • Identify • Independent variable(s): those things the researcher can control • Dependent variables: those things the research can measure • Aside: What is measurable?
Measuring Things • Objectively • Time: to do, to correct, to learn • Counts: tasks performed, errors made • Distance, or other geometrical attributes • Text: density, complexity, reading level • Subjectively • Preference • Rating scale
Good Experimental Design • Limit number of independent variables • Limit number of values for each independent variable • Make dependent variables easy to measure • Develop good working definitions • Control for external bias • Guard against learning and practice
Good Experimental Design (2) • Base hypotheses on theoretical model • Phrase hypotheses in measurable terms • Choose subjects representative of larger group
Example 1 From Goren-Bar, What Do Users Prefer Hypothesis 1: …. users in general will find the user-oriented search method as more suitable for searching the web, compared to search methods that do not consider the user perspective.
Example 1 (continued) Hypothesis 2: Novice and knowledgeable users will not have the same response to both search approaches.
Example 2 From St. Amant, … Navigation and Intelligent Assistance Assume that the precision and recall of an intelligent assistant can be controlled. Hypothesis 1: Is any assistance better than no assistance?
Example 2 (continued) Hypothesis 2: Does task performance change with the precision of the assistance? (Precision = proportion of assistance that is relevant) Hypothesis 3: Does task performance change with the recall of the assistance? (Recall = proportion of relevant information that is provided)
Example 3 From Basgodan, Touch in Shared Virtual Environments Hypothesis: Touch is an essential element in performing a task in a shared virtual environment.
Example 4 From Beck and Shneiderman, HCI course investigations Question:How big should a mouse pad be?
Human Subjects • Informed consent • Minimized risks • Institutional Review Board (IRB) • Expedited review • Application form
Organization • Teams of three • Membership assigned by instructor • Members choose leader, reporter
Items to be Submitted • Initial phase • Team membership preferences • Hypotheses, independent and dependent variables • Bibliography • IRB approval form—includes experimental design and materials • Oral presentation of project • Investigative phase • Progress reports as required
Items to be Submitted (2) • Final phase • Draft of Chapters 1 and 2 of report • Draft of Chapters 3, 4, and 5 of report • Final report: oral and written • Poster abstract and design
Sources for Ideas • CHI Conference Proceedings • ACM Transactions on HCI • Course web site • Your frustrating experiences