Research Design II Flashcards
Pharm. Adeyemi
Explain causal-comparative research
Also known as ex-post facto, it is non-experimental research design used to determine the cause-and-effect relationship between two variables.
In this type of research, the researcher is interested in determining why a particular outcome occurred, and not just in establishing a relationship between variables.
His video????:
Used to establish a correlational relationship between two variables
What is correlation research?
Correlation research is a non-experimental research design used to examine the relationship between two or more variables without manipulating them. It helps determine whether variables are positively or negatively related, or not related at all, but it does not establish causation (cause and effect).
It only measures association, not causation.
What are the characteristics of correlation research?
- Non-experimental: It means that researchers need not manipulate variables with a scientific methodology to either agree or disagree with a hypothesis. The researcher only measures and observes the relationship between the variables without altering them or subjecting them to external conditioning.
- Backward-looking: Correlational research only looks back at historical data and observes events in the past.
- Dynamic: The patterns between two variables from correlational research are never constant and are always changing. Two variables having negative correlation research in the past can have a positive correlation relationship in the future due to various factors.
What is experimental research, and what are the types?
Experimental research is the investigation where one or more independent variables is manipulated to measure the effect on one or more dependent variables. It is based on the cause-and-effect relationship on selected subject matter.
The types are:
1. Pre-experimental design
2. Quasi-experiemental design
3. True experiment
Discuss pre-experimental design and its different forms
Pre-experimental designs is where the researcher studies a single group and provides an intervention during the experiment.
In this case, there is no control group to compare with the experimental group.
Its different forms are:
i. One-shot case study: A single group is exposed to a treatment/stimuli, and outcomes are measured afterward.
ii. One-Group Pretest-Posttest Design: A single group is tested before and after treatment/stimuli.
iii. Static Group Comparison: Two groups are compared, but only one receives the treatment, and there’s no pretest. Testing occurs at the end of the process, allowing the researchers to compare the results from the subjects who received the stimuli against those who didn’t.
What is quasi-experimental design.
Quasi-experiments are studies that aim to evaluate interventions but that do not use randomization. Similar to randomized trials, quasi-experiments aim to demonstrate causality between an intervention and an outcome. They have ever do no randomise the memebers of test groups.
E.g., A hospital introduces a new order-entry system and wishes to study the impact of this intervention on the number of medication-related adverse events before and after the intervention.
Mention 3 reasons why researchers may chose not to randomize trials.
- Ethical considerations: Ethical considerations typically will not allow random withholding of an intervention with known efficacy.
- Difficulty of randomizing subjects
- Small available sample size
Mention 9 threats to the internal validity of quasi-experiments.
- Ambiguous temporal procedure
- Selection
- History
- Maturation
- Regression
- Attrition
- Tesring
- Instrumentation
- Interactive effects
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Explain true experimental research design
True experiments include randomization, a control group, and a treatment group, making them the gold standard for establishing causality. Generally, the purpose is to establish the effect that a factor or independent variable has on a dependent variable.
What are the three factors that must be satisfied in a true experiemnt?
i. There is a control group, which won’t be subject to changes, and an intervention group, which will experience the changed variables.
ii. A variable that can be manipulated by the researcher
iii. Random distribution
Define the following terms:
- Independent variable
- Dependent variable
- Controlled variable
- Independent variable: The variable that the researcher manipulates or changes to see its effect on another variable.
- Dependent variable: he variable that is measured to see if it is affected by the independent variable.
- Controlled variable: These are factors that are kept constant throughout the experiment to ensure they do not influence the dependent variable.
What is randomization?
Randomisation is the process of randomly assigning participants or selecting samples in a study to ensure fairness and eliminate bias. It is commonly used in experimental research to improve the validity of results.
Mention 3 merits of randomization.
- It prevents the selection bias and insures against the accidental bias.
- It produces the comparable groups and eliminates the source of bias in treatment assignments.
- It permits the use of probability theory to express the likelihood of chance as a source for the difference of end outcome.
What are the types of randomisation?
i. Simple (e.g. flipping a coin, using random number generator)
ii. Block (randomizes into groups with equal sample sizes)
iii. Stratified (used to achieve balance among groups in terms of subjects’ baseline characteristics (covariates))
iv. Covariate adaptive stratified (where there may be imbalance among treatment groups, a mix of manual adjustment and pre-assignment is done.)
Mention the steps in the development of an experiment.
- Generate research question
- State a testable hypothesis
- Determine how to control variables in the experiment
- Develop intervention conditions
- Sample from a population
- Determine what empirical measures will be made.
