Chapter 8 Quantitative Research Design Flashcards
Quantitative Research
Uses numbers to represent reality
Analysis between and among variables
Qualitative Research
Uses language, concepts, and words to represent
evidence
Emphasis on process and meaning
Quantitative Design Selection
Explains and verifies facts
Tests theoretical relationships
Predicts events
Quantitative Design Example
What is the relationship between timing of pain
medication, amount of medication, and pain
relief (as measured by a visual analog scale) in
a postoperative population?
Qualitative Design Selection
Captures patient experience
Discovers social process
Describes happenings
Qualitative Design Selection
What is the pain experience like for the patient
postoperatively?
Blueprint
Outlines the plan for the study
-Defined from a broad or narrow perspective
-Connects theoretical perspectives with data collection
and analysis
-Provides methodical direction
-It outlines strategies for sample selection, development of measurement tools, data collection, and data analysis
Design Structure as a Function of Quantitative Dimensions
Strong theoretical base
Explanation among variables
Objective approach to phenomena
Measurement of variables
Precision in measurement
Control of Error: Internal validity
Which type of experimental design offers the strongest evidence for cause and effect?
Randomized Control Trials (RCT) offer the
strongest evidence of whether a cause (an
intervention) results in an effect (a desired
outcome
Characteristics of Experimental Design
Manipulation/Intervention
Control
Random assignment
Intervention
The researcher does something to some subjects (treatment)
-Pre & Post tests
Control
The researcher introduces controls, including the use of a control & experimental groups
Randomization
The experimenter assigns participants to a control or experimental condition on a random basis
Control Group Conditions
No new intervention is used
“Usual care” or standard or normal procedures is used to treat patients.
An alternative intervention is used (e.g., auditory
vs. visual stimulation).
A placebo or pseudointervention, presumed to
have no therapeutic value, is used.
Attention control condition and delayed treatment
(wait-listed)
3 Types of Commonly Used Experimental Designs
1) Randomized pretest-posttest control group
2) Randomized posttest-only group
3) One-group pretest-posttest design
Randomized Pretest-Postest Control Group
One of most commonly seen designs
“Before-and-after” method
Similarity of experimental and control groups
Evaluate dependent variable before independent
variable introduced
Randomized Posttest-Only Control Group
Excludes use of pretest
Usually requires groups to be randomly assigned
Used when pretest is inappropriate or impossible
One-Group Pretest-Posttest Design
Pre-tested on dependent variable then post-tested after treatment
No comparison group
Threats to internal validity
External validity limited
Randomized Clinical Trials
Most widely accepted approach to evaluating intervention or treatment
Researchers strictly adhere to principles of experimental design
Require sufficient sample sizes
Blinding of patients and health-care providers
Single-blinded study
Double-blinded study
Advantages of Experiments
Most powerful method for detecting cause & effect relationships
Disadvantages of Experiments
Often not feasible or ethical, Hawthorne effect (knowledge of being in a study may cause people to
change their behavior), often expensive
Quasi-Experimental Designs
Outcome is “predicted” by theory and research
No random assignment and/or control groups
Nature of study or clinical setting dictate
use of this design
Nonequivalent Control Group Designs
Those getting the intervention are compared with a nonrandomized comparison group
Within-Subjects Designs
One group is studied before and after the intervention
Advantages of Quasi-Experimental Designs
May be easier and more practical than true experiments
