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Research Design & Analysis 1: Class 8

Research Design & Analysis 1: Class 8. Announcements lab partners posting links to on-line journals picketing with Marriott workers sociology seminar final exam: Dec 13th 9:00 -12:00 Chapter 4 review and new stuff Midterm material and format. ASAC picket support.

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Research Design & Analysis 1: Class 8

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  1. Research Design & Analysis 1: Class 8 • Announcements • lab partners • posting links to on-line journals • picketing with Marriott workers • sociology seminar • final exam: Dec 13th 9:00 -12:00 • Chapter 4 review and new stuff • Midterm material and format Psyc2013 Class #8 (c) Peter McLeod

  2. ASAC picket support The Acadia Social Awareness Collective (ASAC) is attempting to organize a day when concerned students can collectively walk the picket lines with the striking workers. ASAC is a small group of students concerned with issues of human rights, social justice etc. We have set Tuesday, October 5 from 12-4 as the time. Psyc2013 Class #8 (c) Peter McLeod

  3. Sociology seminar The Department of Sociology is hosting seminar/discussion session on "Privatization in the University: Implications for the Acadia Community" Wednesday, October 6 from 11:30 to 12:30 in the BAC, Room 244. Psyc2013 Class #8 (c) Peter McLeod

  4. Assessing Validity Does it measures what it is supposed to? Several types/ways to assess • Criterion related (concurrent) validity • agreement with other established measures • Discriminate validity • Construct validity • fit with theoretical construct • Predictive validity • predicts something it should • Face validity • seems reasonable Psyc2013 Class #8 (c) Peter McLeod

  5. Why operational definitions? avoid confusion makes study reproducible makes measurements reliable But trade off between precision of an operational definition and it’s “construct validity” construct validity - fit with theory and/or everyday meaning Psyc2013 Class #8 (c) Peter McLeod

  6. Which operational definition? In practice, use a variety: if all operational definitions give similar results, confident in construct validity Different results with different operational definitions can be informative too. Psyc2013 Class #8 (c) Peter McLeod

  7. Operational Definitions of Stress Phenomena associated with stress Operational definition of stress Overcrowding Gastric ulcers Inescapable shock Depression Sensory deprivation High blood pressure Sleep deprivation In this example, sleep deprivation has low criterion-related or concurrent validity Psyc2013 Class #8 (c) Peter McLeod

  8. Levels (scales) of measurement • Nominal • categorical (difference) information • Ordinal • allows ranking, doesn’t give absolute amounts • Interval • can tell how far apart measures are • Ratio • has absolute zero • When to use each? • Not always clear which scale Psyc2013 Class #8 (c) Peter McLeod

  9. When choosing, consider: • information yielded • nominal - quality • ordinal - some index of quantity • interval - difference information • ratio - how much usually, the more information, the better • statistical tests • measurement scale influences the type of statistics used • ecological validity Psyc2013 Class #8 (c) Peter McLeod

  10. Ecological validity Specific type of external validity • how generalizable are the experimental results to the specific set of external conditions- those of the natural (real-life) context in which the phenomena occurs • particularly important in applied work • may use a composite scale Psyc2013 Class #8 (c) Peter McLeod

  11. Fig 4.1 1 evidence well below a reasonable doubt 2 evidence moderately below ... 3 evidence slightly … 4 evidence slightly above a reasonable doubt 5 evidence moderately above … 6 evidence well above … based on Horowitz et al ‘80 Not guilty Guilty Psyc2013 Class #8 (c) Peter McLeod

  12. Adequacy of Dependent Measures • Sensitivity • Range effects • floor effects • ceiling effects • decrease differences between treatment groups • decreases variance within groups Psyc2013 Class #8 (c) Peter McLeod

  13. Tailoring measures to Participants • Importance that participants understand scales etc. • Infancy examples • habituation & preferential looking, etc. Psyc2013 Class #8 (c) Peter McLeod

  14. Types of dependent variables • Behavioral measures • frequency counts • durations • intervals • latencies • Physiological measures • Self-reports • rating scales (Likert scales) Psyc2013 Class #8 (c) Peter McLeod

  15. Subject reactivity • Psychology experimental are often social situation • Demand characteristics • cues about the study • role attitude cues • cooperative, defensive, or negative • Other influences Note: also an issue in animal research Psyc2013 Class #8 (c) Peter McLeod

  16. Experimenter effects • Experimenter bias • Expectancy effects • threaten both internal and external validity • “Blind” procedures Psyc2013 Class #8 (c) Peter McLeod

  17. Automating experiments • Helps eliminate experimenter effects • Saves time • Makes measures more accurate and less variable but… • May miss important information Psyc2013 Class #8 (c) Peter McLeod

  18. Automating experiments • Video taped instructions • Computer presented stimuli and data collection Psyc2013 Class #8 (c) Peter McLeod

  19. Detecting & correcting problems Pilot studies • clarify instructions • set levels of IV (avoid range effects) • sensitivity of DV • assess reliability & validity of measures • practice • do take time (& possible expense) Manipulation check Psyc2013 Class #8 (c) Peter McLeod

  20. Material covered to Midterm • Ways of knowing • Characteristics of psychological science (Stanovitch) • Scientific explanations (text) • Where to find what is already known • Evaluating questions (ROTI) • Turning questions into hypothesis • Directional vs non-directional hypothesis • Non-experimental designs (characteristics, types, limits of, why/when use them) • Correlations/regressions • Problems in interpreting causation from correlations Psyc2013 Class #8 (c) Peter McLeod

  21. Material covered to Midterm • Experimental research (characteristics, types, limits of, why/when use them) • Types of variables • Validity (internal, external, ecological) • Factors influencing validity • Research settings • Using undergraduates as subjects • Research ethics - Nuremberg code [10 (4)] • NCEHR guidelines • Guiding ethical principles (n=8) • Minimal risk • Violating free and informed consent (when it might be allowed) Psyc2013 Class #8 (c) Peter McLeod

  22. Material covered to Midterm • Scientific observations (systematic) • Problems dealing with big numbers • Operational definitions without distortion (goal) • Evaluating measures (accuracy, reliability & validity) • Types of (measure) validity • Scales of measurement • Today:choosing scale for variables • types and adequacy of DVs • Subject reactivity and experimenter effects • Minimizing problems Psyc2013 Class #8 (c) Peter McLeod

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