Research Methods in Psychology Behavioral Medicine Psy 314

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Research Methods in PsychologyBehavioral
Medicine Psy 314

• William P. Wattles, Ph.D..
• Francis Marion University

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Empirical

• a. Relying on or derived from observation or
  experiment empirical results that supported the
  hypothesis.
• b. Verifiable or provable by means of observation
  or experiment empirical laws.

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Faith Healing gone bad

• NYT 8/29 8-year old died of prayer service
  intended to save him.

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Good science versus bad science

• Alternative explanations.

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Seven Signs of Voodoo Science

• 1. The discoverer pitches the claim directly to
  the media.
• 2. The discoverer says a powerful establishment
  is suppressing his work.
• 3. The effect is at the very limit of detection.
• 4. Evidence for the discovery is anecdotal.

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Seven Signs of Voodoo Science

• 5. The discoverer says a belief is credible
  because it has endured for centuries.
• 6. The discoverer has worked in isolation.
• 7. New laws of nature are proposed to explain the
  observation.

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The Case Study

• A. Widely used, easy to implement.
• B. Allows for a thorough analysis of the
  subject. Useful when phenomena is rare or new
• C. Provides a description
• D. May disconfirm uniform assumptions
• E. Useful for hypothesis generation.

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Disadvantages of case study

• a. Can confuse the individual and the disorder.
• b. Cannot generalize from this idiographic
  (individual) data or to nomothetic ( general)

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Idiographic vs. Nomothetic data

• Idiographic refers to the individual.
• Nomothetic - Of or relating to the study or
  discovery of general scientific laws.
• When we use nomothetic data we gain and. We lose
  specificity to the individual but we gain in that
  we can now generalize to others.

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Correlation

• Observation only
• Relationship one tends to follow the other
• text correlation indicates how similar the
  scores are.
• In general when one increases the other increases
  and vice versa.

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Correlation

• The relationship between two variables X and Y.
• In general, are changes in X associated with
  Changes in Y?
• If so we say that X and Y covary.
• We can observe correlation by looking at a
  scatter plot.

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Type of correlation

• Positive correlation. The two change in a similar
  direction. Individuals below average on X tend
  to be below average on Y and vice versa.
• Negative correlation the two change in the
  opposite direction. Individuals who are above
  average on X tend to be below average on Y and
  vice versa.

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Examples

• Positive correlations Hours spent studying and
  g.p.a. height and weight, exam 1 score and exam
  2 score, Obesity and type2 diabetes,
  hypertension, asthma
• Negative correlations temperature and heating
  bills hours spent watching TV and g.p.a. SAT
  median and taking the test.

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Correlation Coefficient

• One number that tells us about the strength and
  direction of the relationship between X and Y.
• Has a value from -1.0 (perfect negative
  correlation) to 1.0 (perfect positive
  correlation)
• Perfect correlations do not occur in nature

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Strength of Correlation

• Weak .10, .20, .30
• Moderate .40,.50, .60
• Strong .70, .80, .90
• No correlation 0.0

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Advantages of Correlation

• Relatively simple to do.
• Involves observation not manipulation

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Disadvantages of Correlation

• CORRELATION DOES NOT IMPLY CAUSATION

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Correlation

• Measures of health for nations correlate with the
  number of televisions.

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• Obesity increased with popularity of low-fat
  diet.
• More Driving
• Less walking
• Larger portions
• More computes

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EXPERIMENT

• Experimenter Control (manipulation)
• Independent variable
• Dependent variable
• Two or more groups
• experimental group
• control group
• Random assignment

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Independent Variable

• Under control of the experimenter
• Used to explain changes in the dependent variable
• Example Type of instruction
• Should include a control group

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Dependent Variable

• Not under control by the experimenter
• Presumed to be caused or affected by the
  independent variable
• Example grade on final exam

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Random Assignment

• Essential aspect of experiment
• Allows us to control for all potential confounds
• Each subject has an equal chance of being in each
  group.
• Intact groups not random
• Replication to deal with chance variation

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EXPERIMENT

• Double-blind
• to avoid social expectations
• to avoid demand characteristics
• External validity-extent to which we can
  generalize
• Analogue-animals, cold water immersion as stress

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Example of Experiment

• New York Times 9/1/2009
• The Claim Chamomile Can Soothe a Colicky Baby.

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Randomized Clinical Trial

• Independent Variable
• Treatment group
• Chamomile tea
• Control Group
• Other tea
• Dependent Variable
• Presence of colic

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Randomized Clinical Trial

• Results
• Treatment group 57 percent better
• Control group 26 percent better

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Advantage of Experiment

• Can talk about one variable causing another.

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Dose Response Relationship

• A direct, consistent association between an
  independent variable, such as a behavior, and a
  dependent variable, such as a disease.

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Studies over time

• Cross-sectional studies-conducted during only one
  point in time.
• Longitudinal studies follow participants over an
  extend time period.

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Reliability

• Does the test measure consistently?
• text The degree to which test scores are free
  from errors of measurement
• Reliability is necessary but not sufficient

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Measurement Error

• Measurement error is always present
• Anything affecting the test score that does not
  relate to the issue of interest.
• response tendency
• social desirability
• text Variation in scores not due to changes in
  the targeted characteristic.

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Validity

• Does the test measure what it is supposed to
  measure?

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Concurrent Validity

• A type of criterion validity
• Concurrent means at the same time
• Correlate results of one measure with another
  variable
• measured at the same time.
• expected to be related
• Example stress profile correlated to medical
  history.

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Predictive Validity

• Another type of Criterion validity
• Can the test predict something it should be able
  to predict?
• Example, stress profile did not predict symptoms,
  physician visits or self-perceptions of health

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Anti-doping agency seeks test

• A pretty good test is better than no test.
• Bad science
• Positive results from six race specimens must be
  unreliable because he gave six others that tested
  negative.
• there are certainly false positives.
• After exercise 5 were false positives

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Test Accuracy
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New York Times

• The article relates to health psychology in that
  it shows an example of error of measurement.
• Music in the recovery room has a direct
  connection to health psychology because its a
  cognitive distraction it takes the patients
  mind and attention away from the current
  situation and possible pain.

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New York Times

• This is an example of positive correlation. The
  higher (heavier) the woman, the higher (deadlier)
  the cancer
• This article relates to Health Psychology
  because it explains the correlation between the
  occurance of strokes and the time of day.

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New York Times

• The article talks about how people's mind and
  behaviors try to compensate for the idea that
  there is supposedly less nicotine in light
  products.
• High officials emphasizing the importance of
  primary prevention can create a healthier society.

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Epidemiology

• Branch of medicine that investigates the
  frequency and distribution of disease and related
  factors.
• Important in SARS epidemic

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Epidemiology

• Prevalence-the proportion of the population that
  has a particular disease at a specific time.
• Incidence-measures the frequency of new cases of
  the disease.

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Epidemiology

• Determine the etiology or origins of a specific
  disease. To develop and test hypotheses.
• Discovering who is more likely to have a disease
  is useful in determining its cause. SARS as an
  example
• Discovering risk factors such as dirty water or
  smoking.

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Epidemiology

• Mortality- Death rate
• Morbidity-The rate of incidence of a disease.

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Epidemiology

• A risk factor is any characteristic or condition
  that occurs with greater frequency in people with
  a disease than it does in people free from the
  disease.

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Epidemiology

• Presence of a risk factor increases the
  likelihood of developing the illness.

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Epidemiology

• Relative versus absolute risk.Relative
  Considered in comparison with something else
• Relative risk the ratio of incidence or
  prevalence in the exposed group to that of the
  unexposed group
• Absolute risk-The persons chances of developing a
  disease.

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• Test A
• If around 1,000 people have this test every 2
  years, 1 person will be saved from dying from
  this cancer every 10 years.
•  
• Test B
• If you have this test every 2 years, it will
  reduce your chance of dying from this cancer from
  around 3 in 1, 000 to 2 in 1,000 over the next 10
  years.
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• Test C
• If you have this test every 2 years , it will
  reduce your chance of dying from this cancer by
  around one third over the next 10 years.

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Relative Risk

• If you have this test every 2 years , it will
  reduce your chance of dying from this cancer by
  around one third over the next 10 years.

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Absolute risk

• If you have this test every 2 years, it will
  reduce your chance of dying from this cancer from
  around 3 in 1, 000 to 2 in 1,000 over the next 10
  years.

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Number needed to treat

• If around 1,000 people have this test every 2
  years, 1 person will be saved from dying from
  this cancer every 10 years.

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Absolute Risk vs. Relative Risk

• Example New York Times Nov. 08

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Relative Risk 4/850
Absolute risk 8 reduced to 4 A decrease of 4
points or 4 people per hundred
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Quality of care data

• NYT 9/3/04
• More than 98 percent of hospitals in the United
  States are reporting quality-of-care data for
  treating heart attack, heart failure and
  pneumonia, the Centers for Medicare and Medicaid
  Services said yesterday.

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Clinton heart bypass

• During Heart bypass surgery blood vessels are
  taken from elsewhere in the body, often the leg,
  and sewn in to create detours around coronary
  artery blockages
• 516,000 were performed in 2001

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Quality of care data

• Clinton hospital 3.93 deaths per hundred versus
  2.18 for coronary bypass overall in NY.
• Correlational data but they control for 45 risk
  factors.

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Over interpreting data

• Side air bags Reduce the risk of dying in half
• 157/100,000 with side air bags
• 248/100,000 without side air bags

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The End