Research Design PowerPoint Lecture, Dr. Wofford Flashcards
Predictive Correlational Study
Predictive correlational study: Predict a behavior or response based on the observed relationship between that behavior and other variables
- Helps to validate diagnostic/prognostic info (validation of new measurement tool)
- Useful in developing models that can serve as a basis for clinical decision making and to understand factors that impact success with an intervention
Two types of Single Factor Designs for Independant Groups
- Pretest-Postest control group design
- Posttest-only control group design
1 Group Designs: One-way repeated measures design over time (1)
(Quasi-experimental design)
Used with research questions which examine effects of a treatment on physiological or psychological variables and how these effects develop over time
Retrospective vs Prospective research
•Prospective research: measure variables through direct recording in the present.
- •Researcher follows subjects as they progress through the intervention
- •Able to identify factors that influence outcomes
- •More reliable than retrospective studies
Retrospective research: examination of data that have been collected in the past
- •Medical records, surveys, secondary data sets/databases
- •Must question the accuracy of the data since researcher has no control over how the data was collected or variables operationalized
difference between single factor and multifactor designs
Single Factor: 1 IV with any number of levels
Multi-Factor: >1 IV
Single Factor Design for Independed Groups: Pretest-posttest control group design
Pretest-posttest control group design
- •2+ groups that are formed by random assignment
- •One group is the control and the other receives an intervention
- •Could be >1 experimental group
- •Both groups are measured on a DV before and after the intervention
- •Only one IV (group)- debatable (Wofford thought it was a repeated measures design, not really a single factor design because of the type of stats that would have to be used. She disagrees with book, but put it here as book classified.
Multi-Factor Design for Independent Group: Factorial Design:
- 2+ IVs-subjects are randomly assigned to the two variables (2 different types of groups)
- Factors=variables (2-way factor design has two IVs)
- Each factor has levels (3 x 3)- multiply the numbers to know how many groups (ie: 9 groups). very common to our profession.
in 3x3 example, the first 3 is the amount of factors, second 3 is the number of levels per factor
One Group Designs: Time series design (2)
(Quasi-experimental design)
- Often used when studying community interventions or policy changes
- Multiple measurements before and after treatment to document patterns or trends of behavior
NOT VERY COMMON IN OUR PROFESSION
more common in policy change researcher or public health.
Prospective Research
Prospective research: measure variables through direct recording in the present.
- Researcher follows subjects as they progress through the intervention
- Able to identify factors that influence outcomes
- More reliable than retrospective studies
Correlation vs Prediction
Correlational study: Purpose: describe nature of existing relationships among variables
- Correlation: measure of the degree of association among variables
- Provides rationale for clinical decisions or generation of hypotheses (often used to create hypothesese to drive additional studies)
•Predictive correlational study: Predict a behavior or response based on the observed relationship between that behavior and other variables
- •Helps to validate diagnostic/prognostic info (validation of new measurement tool)
- •Useful in developing models that can serve as a basis for clinical decision making and to understand factors that impact success with an intervention
Positive Likelihood Ratio
- Positive likelihood ratio (LR+)= true (+) rate/false (+) rate or sensitivity/1-specificity= indicates how many more times likely a (+) test will be seen in those with the target condition than those without the condition
- LR+>5 represent relatively important effects
Repeated Measures Designs: Multi-factor design
- Two-way design with two repeated measures
- >1 IV (usually time + group)
VERY COMMON
Two Types of Quasi-Experimental Designs
- One-Group Designs
- Multigroup Designs
what design is considered the scientific standard in clinical research for establishing a cause and effect relationship?
Pretest-Posttest Control Group Design
IV has two levels
(it can be configured in different ways)
it is the basic structiore of of an RCT
Posttest Probability
- •Posttest probability: Likelihood that a patient has the target condition after formal testing is conducted
- •A good test should have high posttest probability confirming the diagnosis or low posttest probability causing us to abandon the target condition
Longitudinal Research
Longitudinal study: researcher follows a cohort of subjects over time
- Perform repeated measures at different time intervals
- Able to describe patterns of change
- ie: Framingham heart study
- Threats to internal validity include testing effects (because of repeated measures), attrition, development of confounding variables
Example: Framingham Heart Study
Questionnaires
Questionnaire: structured self-administered surveys using pen & paper or e-formats
- Generally more efficient than interviews
- Provide anonymity
- Primary disadvantage is that there is a potential for misunderstanding questions or response choices
- Low response rate (34% normal)
Predictive Value Estimates
- •A clinical instrument must demonstrate that it is an efficient use of time and resources and that it yields a sufficient number of accurate responses to be clinically meaningful
- •Can be
- Positive Predictive Value or
- Negative Predictive Value
- •Can be
Interviews vs Questionnaires
Interview: researcher asks subjects specific Qs & records answers for later analysis
- Face-face or via telephone
- Major disadvantage is that they are costly and time intensive
•Questionnaire: structured self-administered surveys using pen & paper or e-formats
- Generally more efficient than interviews
- Provide anonymity
- Primary disadvantage is that there is a potential for misunderstanding questions or response choices
- Low response rate (34% normal)
Longitudinal vs Cross-sectional Research
Longitudinal study: researcher follows a cohort of subjects over time
- •Perform repeated measures at different time intervals
- •Able to describe patterns of change
- •ie: Framingham heart study
- •Threats to internal validity include testing effects (because of repeated measures), attrition, development of confounding variables
•Cross-sectional study: researcher studies a cohort of subjects at one point in time and draws conclusions about a population
- •More efficient than longitudinal
Pretest Probabability
Pretest probability: Likelihood that a patient has the target condition before any formal testing is conducted
Three types of EXPERIMENTAL Designs
- •Single factor design for independent groups
- •Multi-factor design for independent groups
- •Repeated measures designs
Multi-Factor Design for Independent Groups: Nested Design (2)
- Commonly used in educational studies
One Group Designs: One-Group pretest-postest design (2)
(Quasi-experimental design)
- One group of subjects receive an intervention and one set of repeated measures is taken before and after treatment
- IV is time with 2 levels (pre and post)
Repeated Measures Designs: 2 types of Single factor designs
- One-way repeated measures design
- Crossover design
Sensitivity vs Specificity
- Sensitivity: ability to obtain positive test when the target condition is really present
- True positive rate
- Increased sensitivity= fewer people with the disorder are missed
- 1-sensitivity= false negative rate
- Snout
- Specificity: ability to obtain negative test when target condition is really absent
- True negative rate
- Increased specificity= fewer people will have false positives
- 1-specificity= false positive rate
- Spin
Three types of One Group Designs (Quasi-Experimental Designs)
- One-group pretest-posttest design
- One-way repeated measures design over time
- Time series design
Case Control Study
Case control study: Groups of individuals are selected on the basis of whether or not they have the disorder/pathology of interest.
- Cases: Have the disorder
- Controls: Don’t have the disorder and serve as a comparsion group
- Advantageous because the samples are relatively easy to obtain and are useful for studying rare disorders
Descriptive Surveys (3 things)
- •Surveys are commonly used to collect information about a specific group
- •Generally focused on a group’s behaviors or attitudes
- •Overall purpose of the descriptive surveys are to provide an overall picture of the group’s characteristics
Systematic Review vs Meta-Analysis
Systematic review: rigorous process of searching, appraising, and summarizing existing information on a selected topic.
- Most commonly focused on the effectiveness of interventions
Meta-analysis: process which combines studies using a quantitative index to develop a single overall estimate of the intervention effect.
- Provide important results when several smaller studies are not sufficient to demonstrate meaningful outcomes
what article should we review to understand these concepts?
the Prone Lochman’s review article
Sensitivity And specificty (2x2 prediction table)
2x2 prediction table