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Flashcards on Experimental Design
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What is the goal of experimental studies?
To investigate relationships between phenomena
What is an independent variable (IV)?
A variable manipulated by the researcher.
What is a dependent variable (DV)?
A variable observed for changes in response to the IV.
Which variable depends on the other, the IV or the DV?
The DV depends on the IV.
On a graph, where are the IV and DV typically placed?
The x-axis and y-axis, respectively.
What is a confounding variable?
A variable that affects both the IV and DV.
How can a confounding variable affect a research study?
It can obscure or exaggerate the true relationship between the IV and DV.
What is a mediating variable?
Provides a causal link between the IV and DV.
What is the relationship between IV, Mediating Variable, and DV?
IV → Mediating Variable → DV
Give an example of a mediating variable.
Quality of healthcare mediating the relationship between income and cancer mortality
What is a moderating variable?
Modulates the intensity or strength of the relationship between IV and DV.
Give an example of a moderating variable.
Coping strategies can moderate the relationship between workplace stress and anxiety.
What is operationalization of variables?
Defining how to measure a variable.
How could daily coffee consumption be operationalized?
Self-reported surveys.
What are experimental studies?
Intentional manipulation of conditions and observation of effects.
What is a negative control?
No treatment or placebo.
What is a positive control?
Receive treatment with known effects, acts as a 'benchmark'.
What are controls used for?
A known treatment to compare the experiment to.
What is randomization?
Random assignment of treatments.
What is blinding?
Not knowing which participant gets what treatment.
What are randomized controlled trials (RCT)?
Participants are randomized into control or treatment groups.
What are observational studies?
Analyze pre-existing data without manipulation.
What are correlational studies?
Investigate interrelations of variables.
What is a cross-sectional design?
Snapshot at one point in time.
What is a limitation of cross-sectional design?
A lack of causal inference.
What are longitudinal studies?
Multiple observations over time.
What are risk factors verses protective factors?
Higher risk vs. lower risk.
What are cohort studies?
(forward in time) or (backwards in time) analysis.
How do cohort studies relate to longitudinal studies?
A subset of longitudinal studies; a group followed over time.
What are case-control studies?
Compare ‘cases’ with a condition to ‘controls’ without it.
What are case studies and series?
In-depth analysis of individual cases or a series of cases.
What is at the top of the hierarchy of evidence?
Systematic reviews and meta-analysis of RCTs at the top.
Why is understanding study design important?
Understanding of study design informs interpretation of research.
Human subject research is overseen by what?
Overseen by Institutional Review Board (IRB).
What is required from the IRB before conducting research?
Approval/exemption required prior to research.
What is social and clinical value in research ethics?
Research must answer important questions.
What is scientific validity in research ethics?
Study must be methodologically sound.
What is fair subject selection in research ethics?
Participants chosen based on scientific goals, access to potential benefits considered.
What is favorable risk-benefit ratio in research ethics?
Minimize risks, benefits must outweigh risks.
What is independent review in research ethics?
External assessment to identify conflicts of interest, ethical concerns.
What is informed consent in research ethics?
Participants informed of study’s purpose, methods, risks, benefits.
What respect for participants in research ethics?
address participants’ privacy, confidentiality, and welfare.
What are fundamentals of research ethics?
Informed consent and risk-benefit analysis crucial.
What studies are used to examine nature vs. nurture?
Twin/sibling studies to examine (nature) vs. (nurture) impact.
What helps identify genetic predictors?
Genetic screening and genome-wide association studies (GWAS).
What is association?
Variables predict each other’s variation.
What is temporality?
Cause precedes effect.
What is plausibility?
Reasonable mechanism for IV to cause variation in the DV.
What is correlation?
Bidirectional relationship, no implication of cause.
What is causation?
Unidirectional, one variable influences another.
What are experimental designs?
Physically control/modulate variables.
What are observational studies?
Use statistical controls/minimize variable effects.
How do independent and dependent variables differ in their roles within an experimental study?
The IV is manipulated by the researcher, while the DV is observed for changes.
Define a confounding variable and provide an example of how it might affect an experimental outcome.
A confounding variable affects both the IV and DV and can obscure the true relationship.
Explain the difference between mediating and moderating variables with examples.
Mediating variables provide a causal link between IV and DV, while moderating variables modulate the strength of the relationship.
How does the operationalization of a variable affect the validity of an experiment?
Operationalization affects the validity of an experiment by determining how accurately a variable is measured.
Why are controls important in experimental research?
Controls help minimize bias and provide a benchmark for comparison.
How does a cross-sectional study design differ from a longitudinal study design, and what are the limitations of each?
Cross-sectional studies are a snapshot in time, while longitudinal studies observe changes over time; cross-sectional lack causal inference.
What makes a randomized controlled trial a strong form of evidence, and why might it still be necessary to conduct other forms of observational studies?
RCTs reduce bias through randomization but observational studies are needed when experiments are not ethical.
Explain the role of an IRB in research and why its approval is important.
The IRB ensures ethical research by reviewing and approving studies involving human subjects.
Discuss the importance of informed consent and how it’s related to the principle of respect for participants.
Ensures participants understand the study to protect their rights.
How might a researcher control for confounding variables in a study examining the effects of a new medication?
Using control groups and statistical methods to adjust for confounders.
Give examples of how understanding the nature versus nurture debate can influence research in psychology and medicine.
It influences the design and interpretation of studies examining genetic and environmental contributions.
How does a correlation differ from a cause-and-effect relationship? Give an example of each.
Correlation indicates a relationship, while cause-and-effect implies one variable directly influences another.
What must phenomena show to be of research interest?
Phenomena must show variation.
Example of confounding variable?
Smoking in coffee drinking and cardiovascular disease research
The purpose of controls is to what?
Minimize bias.
What are the analyses done in cohort studies?
Prospective (forward in time) and retrospective (backwards in time)
Nature vs. Nuture means what?
genetic and environmental.
What are steps to establishing causality?
Association (Correlation), Temporality, and Plausibility.
What depends on the IV?
The DV.
What is scientific validity?
That the study must be methodologically sound
Fundamentals of research ethics
Informed consent, risk-benefit
What are the different kinds of studies related to confounding variables?
Experimental and observational.
What is meant by favorable risk-benefit ratio?
Minimize risks, benefits must outweigh risks
Studies must do what according to research ethics?
To answer important questions
What does independent review provide in research ethics?
External assessment to identify conflicts of interest, ethical concerns
What is at the top of the hierarchy of evidence?
Systematic reviews, Meta Analysis of RCTs
Longitudinal studies help show what kind of inference?
Causal.
What do case control studies do?
To identify variables linked to the outcomes.
What do case studies and series do?
To provide insights into rare conditions or new diseases.
What occurs in experimental studies?
The intentional manipulation of conditions
Experimental studies investigate relationships between what?
The phenomena.
Why is understanding study design important?
Important for health professionals to assess emerging studies
Human subject research is overseen by who?
The IRB
What do twin and sibling studies examine?
The genetic and environmental impacts.
Give an example of a confounding variable.
Smoking as a confounder in coffee drinking and cardiovascular disease research.
Give an example of the operationalization of variables.
Daily coffee consumption could be operationalized through self-reported surveys.
What does the understanding of study design do?
To inform interpretation of research.
What also helps identify genetic predictors in research?
Genetic screening
In an experiment, which variable is manipulated?
the independent variable.
In an experiment, which variable is measured?
the dependent variable.
A mediating variable does what?
provides a causal link
What does a moderating variable do?
Modulates the intensity or strength of a relationship
RCT stands for what?
randomized contolled trials
Why do scientists use blinding and randomization?
To reduce the posibility of bias
Why are cross sectional studies limited?
Because you can't infer cause and effect
What are some risks and outcomes observed in longitudinal studies?
risk factors and protective facters
What is the ethical considerations in all research?
it must be approved by the IRB
When studying nature vs nurture what two variable types are studied?
genetic components and environmental components