Final Written exam - Week 7

Question 1

What are the strengths and weaknesses of a systematic review?

Answer 1

Strengths:
- Efficiency: Saves time for researchers and clinicians by providing a synthesized overview of the evidence.
- Increased Power: Combines data from multiple studies, increasing statistical power and the ability to detect effects
- Reduced Bias: Minimizes bias through a systematic and transparent process.
- Generalizability
- Objectivity

Weaknesses:
- Time-Consuming: Conducting a high-quality systematic review is a resource-intensive process.
- May Not Be Suitable for All Questions: Systematic reviews are most effective for addressing well-defined questions with a substantial body of existing research.
Garbage In, Garbage Out: The quality of a systematic review depends on the quality of the included studies. If the primary studies are flawed, the review will also be flawed.
- Heterogeneity
- Publication Bias

Question 2

What should you consider when critically evaluating a systematic review?

Answer 2

• Clear research question and objectives.
• Comprehensive search strategy.
• Explicit inclusion/exclusion criteria.
• Quality assessment of included studies.
• Appropriate data synthesis and analysis.
• Transparent reporting of findings and limitations.

Question 3

What are the strengths and weaknesses of a meta-analysis?

Answer 3

• Hypothesis Generation: Can identify patterns and sources of heterogeneity, leading to new hypotheses and research directions
• Increased Power: By combining data, meta-analysis increases statistical power, improving the ability to detect true effects, even small ones.
• Resolution of Conflicting Results: Helps to resolve inconsistencies between individual
  study results by providing a weighted average.

Weaknesses:
* Publication Bias
* Heterogeneity
* Apples and Oranges: Combining studies that are too different can lead to misleading conclusions. Careful selection and assessment of studies are essential.
* Statistical Complexity: Requires specialized statistical knowledge and software for proper analysis and interpretation.

Question 4

What should you consider when critically evaluating a meta-analysis?

Answer 4

• Clear research question and eligibility criteria.
• Comprehensive search strategy.
• Assessment of publication bias.
• Assessment and exploration of heterogeneity.
• Appropriate statistical methods.
• Transparent reporting of findings and limitations.

Question 5

What are the strengths and weaknesses of observational studies?

Answer 5

Strengths:
* Real-World Setting: Study participants in their natural environment, increasing generalizability.

• Ethical Considerations: Suitable for studying exposures that cannot be ethically manipulated (e.g.,
  smoking, pollution).
• Multiple Outcomes: Can examine multiple outcomes associated with a single exposure.
• Hypothesis Generation: Can generate hypotheses for future research, including interventional
  studies.

Weaknesses:
* Careful Study Design: Minimize bias through rigorous study design, including appropriate selection of participants and control groups.

• Statistical Adjustment: Use statistical techniques to adjust for potential confounding factors.
• Sensitivity Analysis: Assess the impact of potential biases on the study findings.
• Triangulation: Combine data from multiple sources or study designs to strengthen the evidence.

Question 6

List and briefly describe the three types of observational studies?

Answer 6

Cohort Studies:
* Follow a group of individuals (cohort) over time.
* Assess the incidence of an outcome or disease in relation to exposure to a risk factor.
* Example: Studying the relationship between smoking and lung cancer by following a group of smokers and nonsmokers over several years.

Case-Control Studies:
* Compare individuals with a disease or outcome (cases) to those without (controls).
* Examine past exposures to potential risk factors.
* Example: Comparing the frequency of past head injuries in patients with and without Parkinson’s disease.

Cross-Sectional Studies:
* Collect data at a single point in time.
* Assess the prevalence of a disease or exposure in a population.
* Example: Surveying a community to determine the prevalence of diabetes and its association with obesity.

Question 7

What is the use of an RCT?

Answer 7

A study design that randomly assigns participants to two or more groups to receive different
interventions (e.g., a new drug vs. a placebo).

Question 8

What are the strengths and weaknesses of an RCT?

Answer 8

Strengths:
Causality: The strongest study design for establishing cause-and-effect relationships between an intervention and
an outcome.

Minimizes Bias: Randomization helps to minimize selection bias and confounding factors.

Blinding: Blinding reduces bias from participant and researcher expectations.

Statistical Analysis: Allows for rigorous statistical analysis to determine the magnitude and significance of the
effect.

Gold Standard: Widely considered the gold standard for evaluating the effectiveness of interventions.

Weaknesses:
* Artificial Setting: May not fully reflect real-world conditions due to strict eligibility criteria and controlled
environments.

• Ethical Considerations: May not be ethical to withhold or provide certain interventions in some situations.
• Costly and Time-Consuming: RCTs can be expensive and require a long follow-up period.
• Generalizability: Findings may not be generalizable to all populations due to strict inclusion/exclusion criteria.
• Compliance: Participant adherence to the assigned intervention can be challenging.

Question 9

What are the three types of blinging used in an RCT?

Answer 9

Single-blind (participants blinded)

Double-blind (participants and researchers blinded)

Triple-blind
(participants, researchers, and data analysts blinded).