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Research Lecture2 Research Approaches
 

Research Lecture2 Research Approaches

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Research Lecture2 Research Approaches Research Lecture2 Research Approaches Presentation Transcript

  • Research Methods Lecture 2 Non-experimental and Experimental Research Approaches Chapters 2 & 3
  • Research Designs/Approaches Gender differences in visual/spatial abilities Moderate to high Current or past Test for cause/ effect relationships without full control Quasi-experi-mental Comparing two types of treatments for anxiety. High current Test for cause/ effect relationships Experi-mental Examples Degree of control Time frame Purpose Type
  • Research Designs/Approaches Relationship between history of child abuse & depression. Low to medium Past & current Examine the effect of past event on current functioning. Ex post facto Relationship between studying style and grade point average. Low to medium Current (cross-sectional) or past Examine relationship between two variables Non-experimental - corre-lational Examples Degree of control Time frame Purpose Type
  • Research Designs/Approaches How mother-child negativity changed over adolescence. Low to moderate Future Examine change in a var. over time in overlapping groups. Cohort-sequen-tial Relat. betw. history of depression & development of cancer. Low to moderate Future -predictive Examine relat. betw. 2 var. where 1 is measured later. Non-experimental -corre-lational Examples Degree of control Time frame Purpose Type
  • Research Designs/Approaches People’s experiences of quitting smoking. None or Low Past or current Discover potential relationships; descriptive. Quali-tative Voting preferences before an election. None or low Current Assess opinions or characteristics that exist at a given time. Survey Examples Degree of control Time frame Purpose Type
  • Non-experimental Research Designs
    • Describes a particular situation or phenomenon.
    • Hypothesis generating
    • Can describe effect of implementing actions based on experimental research and help refine the implementation of these actions.
  • Correlational Design
    • Measure two variables
      • Study methods and grade-point average
    • Determine degree of relationship between them
      • Correlation coefficient (e.g., r = 0.50)
    • Allows description and prediction of the relationship
  • Correlational Studies
    • Type of descriptive research design
      • Advantage is that it can examine variables that cannot be experimentally manipulated (e.g., IQ and occupational status).
      • Disadvantage is that it cannot determine causality.
      • Third variable may account for the association.
      • Directionality unclear
  • Origins of the Correlation Coefficient Children’s height Parent’s height Correlation between parent’s height and children’s height 2 3 4 6 4 3 65” 6 8 11 11 8 6 66” 10 13 14 13 11 7 67” 2 12 12 10 6 3 68” 9 9 8 5 3 2 69” 5 5 4 2 70” 69” 68” 67” 66” 65” 64”
  • Correlation Scatterplot Strong Positive Relationship
  • Correlation Scatterplot Strong Negative Relationship
  • Correlational Designs
    • What are some correlational studies that you can do?
  • Ex Post Facto Study
    • Variable of interest is not subject to direct manipulation but must be chosen after the fact.
    • E.g., Define two groups of people according to a certain characteristic (e.g., history of trauma) and measure how they respond in terms of anxiety to a certain stimulus (e.g., watching violent film).
    • Limitation – self-selection bias, cohort effects may explain the effect.
  • Personality and Hypertension, Effect of Hypertension Awareness
  • Personality and Hypertension: Effect of Hypertension Awareness 89 89 75 75 % Male 118.5/ 75.7 (10.3/4.8) 135.8/ 93.8 (8.2/3.4) 118.7/ 76.3 (11.5/5.5) 135.1/ 93.9 (9.2/5.1) SBP/DBP Mean* (SD) 45.8 (8.0) 46.4 (8.3) 46.2 (8.2) 46.2 (9.2) Age Mean* (SD) Group 4 Normo-tensive Group 3 Unaware Hyper-tensive Group 2 Normo-tensive Group 1 Aware Hyper-tensive Variable
  • Personality and Hypertension: Effect of Hypertension Awareness * Group 1 > Group 2 & Group 3 (p < 0.01) -2.6 (8.2) -2.0 (9.4) -3.0 (9.4) 0.79 (8.5) Type A Mean* (SD) 9.5 (4.6) 9.7 (4.8) 9.3 (5.3) 12.0 (5.3) Neuro-ticism Mean* (SD) Group 4 Normo-tensive Group 3 Unaware Hyper-tensive Group 2 Normo-tensive Group 1 Aware Hyper-tensive Variable
  • Personality and Hypertension: Effect of Hypertension Awareness Aware hypertensive > normotensive & unaware hypertensive, P < 0.001
  • Personality and Hypertension: Conclusion
    • Do hypertensives have a different personality than those with normal blood pressure?
      • No, because the unaware hypertensives did not differ from the normotensives.
    • Why did the aware and unaware hypertensives differ?
      • Possible explanations?
  • Personality and Hypertension: Conclusion
    • Awareness of hypertension status confounds assessment of the association between personality characteristics and hypertension.
      • Due to hypertension labeling effect; or
      • Due to self-selection bias
  • Cross-Sectional Study Designs
    • Compares groups at one point in time
      • E.g., age groups, ethnic groups, disease groups.
    • Advantage is that it is an efficient way to identify possible group differences because you can study them at one point in time.
    • Disadvantage is that you cannot rule out cohort effects.
  • Longitudinal Design
    • Gathers data on a factor (e.,g. confidence) over time.
    • Advantage is that you can see the time course of the development or change in the variables
      • Confidence increasing with age.
      • Confidence increasing at a faster rate in the 30’s than the 40’s.
      • Confidence decreasing in the 50’s and 60’s.
      • Disadvantage is it is costly and still subject to bias
  • Cohort-Sequential Design
    • Combines a bit of the cross-sectional design and longitudinal design
      • E.g., Different age groups are compared on a variable over time.
    • Advantage – very efficient and reduces some of the biases in the cross-sectional design since you can see the evolution of change over time.
    • Disadvantage – cannot rule out cohort bias or the problem of the ‘unidentified’ third variable accounting for the change.
  • Naturalistic Observation
    • Aims to unobtrusively observe behaviour in the natural setting.
    • Observing in the natural setting enables one to minimize or eliminate the problem of artificial behaviour in response to being studied (i.e., reactivity effects).
    • One variation is being a participant observer (e.g., undercover agent).
  • Naturalistic Observation
    • Advantages
      • Observe the natural phenomena (not artificial)
    • Disadvantages
      • Observer bias
      • Reactivity in subjects
      • Ethics
  • Meta Analysis (Glass 1976)
    • Quantitative approach to integrate and describe results across a range of independent studies.
    • Enables you to combine the probability (p) value for statistical tests over a number of studies.
    • Enables you to determine the effect size of the independent variable (e.g., treatment group) across studies.
  • Survey Research
    • Collecting standarized information from people using an interview or self-report format.
    • Typically survey knowledge or opinions.
    • To standarized the information one uses a questionnaire with set questions.
    • Ideally the questionnaire has been validated.
    • Representativeness of the sample is very important.
  • Survey Methods
    • Interviews
      • Advantage - Comprehensive, ensure participant understands the question, minimizes missing data, enables clarification of unclear responses
      • Disadvantage – expensive, people more like to refuse participation, can be risky for interviewer, interviewer may bias the responses.
  • Types of Survey Methods
    • Face-to-face interviews
      • Expensive and time-consuming
    • Telephone interviews
      • Need to use random-digit dialing to reach both listed and unlisted numbers.
    • Mail
      • Return rate is usually low (20-30%).
  • Types of Questions
    • Open-ended
      • E.g., Can you tell me about your typical experience with dating?
    • Close-ended
      • E.g., How do you typically meet someone to date?
        • Introduced by someone
        • Social event
        • In university class or place of work
        • At a bar
        • Through sports or other athletic events
  • Sampling
    • Population is everyone in your population of interest.
    • Sample is some proportion of the population.
    • Haphazard sampling – convenience sample
    • Random sampling
      • There is always some degree of sampling error.
  • Qualitative Methods
    • Multimethod approach to studying people in their natural environment
      • It is interpretive – researcher has to make sense of the data
      • Multimethod – can use interviews, photographs, natural observation, archives, etc.
      • It is typically conducted in person’s natural environment.
    • Valuable to use when phenomenon not fully defined.
  • Qualitative Methods Limitations
    • Participant’s observations and accounts can be biased. For example, filtered by his/her style of expression, gender, social class, race, age, ethnicity, etc.
    • People are seldom able to provide a true and full account of their experience.
      • Defensive
      • Lack insight
      • Unaware
  • Qualitative Methods Transcripts
  • Experimental Designs
    • Examines differences between experimentally manipulated groups or variables (e.g., one group gets a certain drug and the other gets a placebo).
    • At minimum, experimental (independent) variable has two levels (e.g., drug vs. placebo).
      • Advantage is that you can determine causality.
      • Disadvantage is cost and many variables cannot be experimentally manipulated (e.g., smoke exposure over time).
  • Experimental Designs Four Canons for Identifying Causality
    • Method of Agreement –
      • Observe the element common to several instances of the event
      • Problem is you may inadvertently overlook a significant variable.
    • Method of Difference –
      • Identify the different effects produced by two situations that are alike in all ways but one.
      • Fairly robust and strong method.
  • Experimental Designs Four Canons for Identifying Causality
    • Joint methods of agreement and difference
      • Observe the element common to several instances of the event
      • Form hypothesis based on observations
      • Test hypothesis using method of difference
    • Method of Concomitant Variation –
      • Identify the different effects produced by more than two situations that are alike in all ways but one.
      • E.g., Compare two active drugs to a placebo
  • Experimental Design
    • Because it is so difficult with human behaviour to demonstrate causation unequivocally, some argue that a theory or prediction can only achieve the status of “not yet disconfirmed” (Popper, 1968).
    • Our scientific efforts are directed at finding the causal factors rather than ‘the cause’ per se.
  • Psychological Experiment: Is Objective
    • Researcher strives for freedom from bias.
    • Recognize that:
      • Mistakes can occur
      • Carefully scrutinize all steps of the experiment to identify where mistakes are likely.
      • Take the steps necessary to minimize error.
  • Psychological Experiment: Focuses on a Phenomenon
    • This is a publicly observable behaviour.
      • Actions
      • Appearances
      • Verbal statements
      • Responses to questionnaires
      • Physiological responses.
  • Psychological Experiment: Is Done Under Strictly Controlled Conditions
    • Eliminate all factors that could influence the outcome other than the factor being manipulated.
    • Control is needed to infer causation.
    • All conditions are kept constant except one; the manipulated variable.
    • The variable of interest is varied in order to test its effect.
  • Experimental Method
    • Advantages
      • Strength with which causal relationships can be inferred.
      • Ability to manipulate one or more variables.
      • Proven to be a very useful and robust scientific method (i.e., withstood the test of time).
  • Experimental Method
    • Disadvantages
      • Tight controls often produce artificial conditions that could limit the generalizability of the findings (i.e., internal vs. external validity trade-off).
      • Time consuming.
      • Expensive.
      • Human behaviour is very complex and cannot be fully studied using experimental methods.
  • Experimental Method: Threats to Internal Validity
    • Learning or practice effects
      • Scores on a measure change on repeat testing because participant has more familiarity with the measure and so answers more truthfully.
    • Natural history effects
      • Something happens in the social background (e.g., society because more affluent generally) and this influences the participant’s responses.
    • Maturation
      • Natural developments in the participant account for the changes (e.g., getting older).
  • Experimental Method: Threats to Internal Validity
    • Regression to the mean
      • High scores generally move down toward the mean and low scores move up.
    • Instrumentation
      • If pre and post tests are not equivalent in all ways (e.g., difficulty, readability) then differences observed may be due to ‘instrumentation’ differences rather than due to your experimental manipulation.
  • Experimental Method: Threats to Internal Validity
    • Subject problems
      • Selection bias (e.g., participation rate).
      • Attrition (e.g., only motivated subjects stay in the experiment).
  • Experimental Method: Threats to External Validity
    • Subject variables
      • Selection bias.
      • Attrition bias
    • Artificial conditions
      • E.g., In order to measure a subject’s blood pressure in response to a well-fined stressor you bring him/her into the laboratory but his/her response in the laboratory may not reflect how his/her blood pressure would really respond under stress in his natural environment.
  • Let me know…
    • If there are any topics from today’s lecture that need fuller explanations.
    • Anything you particularly liked about the lecture (today’s or others as we go along).
    • Anything you particularly disliked about the lecture (today’s or others as we go along).