Experiments and statistics

QNT, Paul Cairns, University of York2 Classic “lab” study  Studying cause and effect – “novel navigation for faster task times”  But it might be something else…  Ensure causal chain

QNT, Paul Cairns, University of York3 Big problem  People vary – Unlike say gravity or water  Context influences people  Need to isolate causal chain  Need to account for natural variation

QNT, Paul Cairns, University of York4 Experimental design  Independent variable (IV) – Causes change in  Dependent variable (DV) – Which is numeric  Confounding variables – Are eliminated

QNT, Paul Cairns, University of York5 Statistics  Accounts for natural variation  Assume IV has no effect (null)  Prediction is crucial  Calculate probability of DV data  Unlikely data suggests real effects

QNT, Paul Cairns, University of York6 Challenges  Hard concepts: involvement, aesthetics – Construct validity  Context – External/ecological validity  Very small questions

Surveys and interviews

QNT, Paul Cairns, University of York8 How to ask questions  Questionnaires  Interviews  Focus groups

QNT, Paul Cairns, University of York9 Outcomes  Demographics  Reveal thoughts/opinions/experiences  Formulate new hypotheses  Measurement – Questionnaire as instrument

QNT, Paul Cairns, University of York10 Asking questions  Closed – Likert scales – Options  Open  Wording

QNT, Paul Cairns, University of York11 Bad questions  “Why don’t you like this interface?”  “Isn’t this good?”  “We made this. What do you think of it?”  “I don’t like the colours and would prefer a simpler interaction: Agree?”  “How old are you?”

QNT, Paul Cairns, University of York12 Analysis  Closed questions: counting and stats  Open questions: coding – Patterns, themes – Dimensions and attributes – Theoretical sampling

QNT, Paul Cairns, University of York13 Challenges  Learning to ask questions  Qualitative analysis  Informing design

Case studies

QNT, Paul Cairns, University of York15 Misconceptions  Sample of one  “Go in and learn”  Purely descriptive

QNT, Paul Cairns, University of York16 Characterising Case Studies  Current  Context and object blur  Multiple sources of evidence  Theoretically informed

QNT, Paul Cairns, University of York17 Outline of process  Theoretical prediction  Gather data – Obs, interviews, documents, resources  Analyse – Maintain causal chain  Theoretical development

QNT, Paul Cairns, University of York18 Methodological development  Devise method to address problems  Use method in a project  Analyse impact of method  Develop method

QNT, Paul Cairns, University of York19 Challenges  No formal analysis methods  Often need intervention  Action Research for HCI? – Notion of participation – Joint solutions