Lesson 4 Flashcards
refers to the plan, structure, and strategy of research; the blueprint that will guide the research process.
Research Design
Research Design may be developed
-to find out the nature of phenomenon,
-to generate a hypothesis of relationship, or
-to test a hypothesis
The test for the quality of the studies research design is the study’s _____
conclusion validity
refers to the extent of researcher’s ability to draw accurate conclusions from the research.
CONCLUSION VALIDITY
correctness of conclusions regarding the relationships among variables examined.
Internal Validity
Generalizability of the findings to the intended/appropriate population/setting
External Validity
Guiding principle for effective control of variances (and, thus, effective research design) is:
THE MAXMINCON PRINCIPLE
MAXmize systematic variance
MINimize error variance
CONtrol variance of Nuisance/Extraneous/Exogenous/Confounding variables
simulates absence of X
CONTROL GROUP
GENERAL METHODS OF DATA COLLECTION:
Review of Documents
Query
Observation
This means getting the true value or measurement.
Accuracy
ability of the data collection tool to measure what it is supposed to measure
Validity
capacity to pick up or label positive those who have the disease.
sensitivity
capacity of the test to exclude or label negative those who do not have the disease.
specificity
the chance than a positive result is truly indicative of
the presence of the disease or condition.
positive predictive value
ability of the tool to give the same or identical results when the test is done on the same subject by different observers. It eliminates observer bias
Objective
Ability of the measuring device to give consistent results. Standard deviation or variance measures precision; the greater its value the lower is the
precision
Precision, Repeatability or Reliability
MAXIMIZING SYSTEMATIC VARIANCE:
IN EXPERIMENTS: (where the researcher actually manipulates the independent variable and measures its impact on the dependent variable):
IN NON-EXPERIMENTAL STUDIES: (where independent and dependent variables are measured simultaneously and the relationship between them are examined):
MINIMIZING ERROR VARIANCE (MEASUREMENT ERROR):
Increase validity and reliability of measurement instruments.
Measure variables under as ideal conditions as possible
Sources of error variance:
Poorly designed measurement instruments (instrumentation error).
Error emanating from study subjects (e.g., response error).
Contextual factors that reduce a sound/accurate measurement instrument’s capacity to measure accurately.
HOW TO CONTROL FOR CONFOUNDING/ NUISANCE VARIABLES:
In Experimental Settings:
Conducting the experiment in a controlled environment (e.g., laboratory).
Subject selection (e.g., matching subjects in experiments).
Random assignment of subjects (variations of confounding variables are evenly distributed between the experimental control groups)
In Survey Research:
Sample selection (e.g., including only subjects with appropriate characteristics-using male college graduates as subjects will control for potential confounding effects of gender and education)
Effective research design is a function of?
✓ Adequate (full range of) variability in values of research variables,
✓ Precise and accurate measurement,
✓ Identifying and controlling the effects of confounding variables, and
✓ Appropriate subject selection
Experimental Designs
True Experimental Studies
Non-Experimental Designs
Expost Facto/Correlational Studies
One of the simplest experimental designs is the
ONE GROUP PRETEST-POSTTEST DESIGN-EXAMPLE
be aware of the _______ (it tends to prejudice the results especially in medical research).
SOLUTION: _______ (neither the subjects nor the experimenter knows who is getting the placebo/drug).
Experimenter Effect…Double Blind Experiments
potential confounding fact in experimental studies:
Hawthorne Effect
History: Biasing events that occur between pretest and post-test
Maturation: Physical/biological/psychological changes in the subjects
Testing: Exposure to pretest influences scores on post test
Instrumentation: Flaws in measurement instrument/procedure
(regression toward the mean)?
Subjects selected based on extreme pretest values
Discovered by in 1877
Statistical Regression
Differential drop-out of subjects from experimental and control groups during the study
Experimental Mortality
Important Features of True Experimental Designs
- PRESENCE OF A COMPARISON GROUP
- RANDOMIZATION
- BLINDING
- PROGNOSTIC STRATIFICATION
Important Features of True Experimental Designs
- PRESENCE OF A COMPARISON GROUP
- RANDOMIZATION
- BLINDING
- PROGNOSTIC STRATIFICATION
At Least Four Other Possible Interpretations/Reasons For Correlations Between Two Variables:
Both variables are effects of a common cause
Both var. alternative indicators of same concept
Both parts of a common “system” or “complex;” tend to come as a package
Fortuitous–Coincidental correlation, no logical relationship
John Stuart Mill’s Rules for Inferring Causal Links
- Covariation Rule (X and Y must be correlated) - Necessary but not sufficient condition.
- Temporal Precedence Rule (If X is the cause, Y should not occur until after X).
- Internal Validity Rule (Alternative plausible explanations of Y and X-Y relationships should be ruled out (i.e., eliminate other possible causes).
STEPS IN PLANNING FOR DATA COLLECTION:
1.Identify the data to be collected
2.Determine the possible sources of data
3.Choose the method appropriate for the study
4.Prepare the tools of data collection
5.Establish the time-frame of data collection, considering the number of subjects, the time needed to collect the data per subject, and the number of personnel for the work.
The plan of data collection includes:
✓The data or information to be collected.
✔How information are to be collected including the tools to be used.
✔How quality control is to be ensured and the different forms of bias are to be eliminated. ✓Time table for data collection including how this is estimated.
GENERAL METHODS OF DATA COLLECTION:
Review of Documents
Query
Observation
TOOLS OF DATA COLLECTION:
- Questionnaire is essential for asking questions.
- Devices and tests are needed in the assessment of the outcome of process.
CRITERIA FOR CHOOSING THE METHOD OF DATA COLLECTION:
✓Accuracy of the information generated by the method.
✓ Practicability of the method
