Pro Quiz on Chapters 13, 14, 15, 16

Question 1

Define exploratory research

Answer 1

Exploratory research: the systematic investigation of relationships among 2 or more variables Example: Gary’s study

Question 2

Compare and contrast longitudinal research with cross-sectional research

Answer 2

Longitudinal research: researcher follows a cohort of subjects over time, performing repeated measurements at prescribed intervals Cons: long commitment of funds & resources Internal validity treats: 1. testing effects: due to subjects being tested repeatedly 2. attrition: due to long collection time 3. confounding variables Cross-sectional research: researcher studies a stratified group of subjects at one point in time and draws conclusions about a population by comparing the characteristics of those strata Used more often than longitudinal due to efficiency Not threatened by testing or history effects b/c subjects are only tested once Internal validity threats: 1. Selection

Question 3

Explain correlation and regression

Answer 3

Correlation: r - a measure of the degree of association among variables - based on “covariation in data” - does not imply causation Regression: r2 - “Prediction” - statistical technique used to establish the accuracy of prediction

Question 4

Compare and contrast case control and cohort study design

Answer 4

Both: - Intended to study risk factors - association between disease & exposure Case control: - groups of individuals are selected based on whether or not they have the disorder under study - examine if exposure is different between cases and control Case: those with disorder Controls: comparison group without disorder Pros: 1. good in studying disorders that are rare 2. retrospective Cohort study design: - selection of a group who do not yet have the outcome of interest, and follows them to see if they develop the disorder - usually prospective - Examine if different incidence of disease Pros: 1. ability to determine the onset of the condition Con: 1. Not useful for rare conditions

Question 5

Outline considerations for selection of subjects in case control and cohort studies and potential for bias

Answer 5

Case control: - controls should be selected from the same population as the cases - match cases and controls on a variety of factors: age, race, gender or occupation Bias: 1.. selection bias 2. self-selection bias 3. observational bias 4. interviewer bias 5. recall bias 6. misclassification Cohort: - selection based on exposure or not - less concern for bias b/c classification of exposure is made independently of knowledge of subject’s disease status Bias: 1. misclassification