Experimental Design Flashcards
What is the purpose of randomization in an experimental design?
It reduces bias by ensuring that each participant or subject has an equal chance of receiving any treatment.
Why is blinding used in experiments?
Blinding minimizes bias by preventing participants, and sometimes researchers, from knowing which treatment (if any) the participants are receiving.
What are control groups, and why are they important?
Control groups do not receive the treatment being tested and serve as a benchmark to measure the effects of the treatment.
Describe the process of factorial design in experiments.
It involves multiple factors being tested simultaneously, allowing interactions between factors to be analyzed.
What is the role of replication in experimental design?
Replication increases the reliability of the results by reducing the impact of random variations.
How does blocking improve experimental accuracy?
Blocking groups similar subjects together, reducing variability and improving the accuracy of the conclusions.
What are crossover designs, and when are they used?
Crossover designs involve participants receiving multiple treatments in a sequential manner, useful for comparing treatments within the same subjects.
What is the significance of baseline measurements in controlled trials?
They allow comparisons to be made pre and post-intervention, establishing a baseline to measure change.
What ethical considerations must be addressed in experimental design?
Ethical considerations include ensuring participant safety, informed consent, and maintaining confidentiality.
How do you determine the sample size for an experiment?
Sample size is determined based on expected effect size, variance, and desired power level.
What is a pilot study, and why is it important?
A pilot study tests the feasibility of the experiment and helps refine the procedures before a full-scale study.
How does random assignment influence the validity of an experiment?
Random assignment ensures that each group is similar in all respects except for the treatment, enhancing the validity of the results.
What are the benefits of using a placebo in clinical trials?
Placebos help distinguish between the actual effects of the treatment and the psychological effect of receiving a treatment.
How do you handle missing data in experimental research?
Missing data can be handled by various imputation techniques or by using robust statistical methods that accommodate missingness.
What is the difference between internal and external validity?
Internal validity refers to how well the experiment is conducted, external validity to how well the results can be generalized.
Why is the double-blind method considered the gold standard in experimental design?
It prevents both the participants and the researchers from knowing the treatment allocation, reducing bias.
What is a confounding variable, and how can it be controlled?
A confounding variable is an extraneous variable that correlates with both the dependent and independent variables, controlled through randomization or design.
How do you ensure the reliability of experimental results?
Reliability can be ensured through replication, precise measurements, and controlled conditions.
What is the purpose of a pretest-posttest design?
It assesses changes in outcomes after a treatment, comparing measurements taken before and after the intervention.
How do you interpret interactions in a factorial design?
Interactions show how the effect of one factor depends on the level of another factor.
What are adaptive designs in clinical trials?
Adaptive designs allow modifications based on interim results, improving efficiency and ethical aspects of clinical trials.
How does stratification enhance experimental design?
Stratification ensures that subgroups are evenly represented, improving balance and accuracy.
What are the limitations of quasi-experimental designs?
They lack random assignment, making causal inferences less reliable.
Why is counterbalancing used in psychological experiments?
Counterbalancing is used to minimize the effects of order in repeated measures designs, where each subject receives treatments in a different order.
What role does the Hawthorne effect play in experimental design?
It refers to changes in behavior resulting from the awareness of being observed, which can influence outcomes.
How do you assess the statistical power of an experiment?
Statistical power is assessed by calculating the probability that the experiment will detect an effect, if there is one, based on the sample size and effect size.
What are the implications of a high attrition rate in longitudinal studies?
High attrition can bias the results, making it difficult to generalize findings from the remaining participants.
How do you validate the outcomes of an experiment?
Validation involves confirming that the instruments and methods accurately measure what they are intended to measure.
What is the difference between observational and experimental studies?
Observational studies observe outcomes without manipulating variables; experimental studies involve manipulation to observe effects.
What strategies can be employed to minimize bias in experiments?
Bias can be minimized through randomization, blinding, and proper experimental controls.
How do you ensure ethical treatment of participants in experiments?
Ethical treatment includes ensuring no harm comes to participants, providing full disclosure about the experiment, and securing informed consent.
What is the importance of informed consent in clinical trials?
It ensures participants are aware of the risks and benefits, and agree to participate under known conditions.
How do you determine if an experimental design is robust?
A design is robust if it consistently produces reliable results under various conditions.
What is sequential analysis, and when is it useful?
Sequential analysis allows for data to be evaluated as it is collected, potentially ending the study early if results are significant.
Why are crossover designs beneficial in medical research?
They reduce patient exposure to less effective treatments and allow multiple treatments to be tested within the same individual.
How can the results of an experiment influence policy decisions?
Experimental results can provide evidence to support or reject policy approaches, influencing decisions in healthcare, environmental policy, and more.
What are the best practices for documenting experimental procedures?
Documenting procedures ensures the experiment can be replicated and results can be verified by others.
How do control variables differ from independent variables?
Control variables are kept constant to isolate the effect of the independent variable on the dependent variable.
What are the challenges in designing experiments for complex systems?
Complex systems pose challenges due to interactions, feedback loops, and emergent behavior, requiring sophisticated designs.
How do you handle ethical dilemmas that arise during experiments?
Ethical dilemmas are handled by prioritizing participant welfare, adhering to ethical guidelines, and seeking advice from review boards.
