Review on Biases, Validity, and Research Methodologies in Clinical Studies

These flashcards cover key concepts related to biases, validity, study types, and research methodologies in clinical studies, aiding in exam preparation.

What is selection bias?

A difference in basic characteristics of the control/experimental group and the population we want to study.

What is performance bias?

When different groups are treated differently, affecting the study results.

What is attrition bias?

Reduction in number of participants where dropouts have different characteristics from those who remain.

What is publication/reporting bias?

Systematic reporting of some outcomes while neglecting others, affecting the body of evidence.

What is confounding bias?

A variable that impacts the outcome but is not the focus of the study.

What does internal validity refer to?

The extent to which a study's results can be attributed to the intervention being studied.

How does internal validity relate to study design?

Internal validity assesses the integrity of a study's design, methodology, and execution.

What impacts internal validity?

Any biases that affect a study's results.

Name a method to improve internal validity.

Blinding, matching, restriction, or randomization.

What is external validity?

The generalizability or applicability of a study's findings beyond the specific study population.

What impacts external validity?

The setting, participants, and operators of the study.

How can external validity be improved?

Using random sampling, large sample size, and making the intervention cost-effective.

What is an RCT?

A study type that compares different interventions and determines causal relationships.

What is a benefit of RCT?

Randomization removes selection and confounding biases.

What are limitations of RCT?

Ethical concerns, financial costs, and organizational demands.

How do RCTs remove selection bias?

By randomly allocating patients to control or experimental groups.

What is patient blinding?

A method to avoid placebo effects in participants.

What is operator blinding?

A method to avoid performance bias during the intervention.

What is the P value?

The probability that an event occurred due to chance, with significance set at below 0.05.

What does statistical significance indicate?

The observed effect between groups is unlikely to have occurred by chance.

What does clinical significance refer to?

The practical importance of observed effects or differences in a clinical study.

How does effect size help assess clinical significance?

By measuring the magnitude of the difference between groups.

What is absolute risk reduction (ARR)?

The difference in risk of an event between the control and treatment group.

What is relative risk reduction (RRR)?

The percentage reduction in risk between the exposed and non-exposed groups.

What is NNT?

Number Needed to Treat, indicating how many patients need treatment to see one benefit.

What does CI stand for?

Confidence Interval, the range where we are confident the true result lies.

What is a cohort study?

A study that follows a group sharing a common characteristic to observe outcomes.

What are the types of cohort studies?

Prospective and retrospective studies.

What is a key advantage of cohort studies?

They can provide insight into possible causal relationships.

What is a key disadvantage of cohort studies?

They are not randomized, so confounding variables can be an issue.

How is internal validity improved in cohort studies?

Through matching participants and restricting confounding variables.

What is relative risk?

The risk of an outcome in the exposed group compared to the non-exposed group.

What does an odds ratio indicate?

Comparison of the odds of an outcome in the exposed group to the unexposed group.

What are Bradford Hill’s criteria?

Criteria to judge whether an association is causal based on several factors.

What is a systematic review?

Secondary research that collects and assesses primary studies on a similar question.

What is a meta-analysis?

Combination of results from similar studies to provide an average outcome.

What does a risk of bias table indicate?

Assessment of the risk of bias in different domains of included studies.

What is a Forest plot?

A graphical representation to compare results of multiple studies in a systematic review.

What are clinical guidelines?

Evidence-based recommendations for managing specific clinical conditions.

What process do guidelines undergo?

Deciding on the topic, recruiting groups, searching for research, and appraising evidence.

What can compromise guideline quality?

Biases from experts, poor search methods, and lack of critical appraisal.

What is GRADE?

A system to determine the certainty of evidence behind a recommendation.

Why do guidelines need to be reviewed?

To ensure they are up-to-date and reflect current evidence in clinical practice.