1. Surveys
Strengths: Can reach a large population, relatively low cost, and can be conducted online.
Limitations: Subject to self-report bias and low response rates.
2. Interviews
Strengths: Can provide in-depth information, and higher response rates.
Limitations: Time-consuming and may introduce interviewer bias.
3. Observational Studies
Strengths: Real-world data, can study rare conditions.
Limitations: Cannot establish causality, potential for confounding variables.
4. Case-Control Studies
Strengths: Efficient for rare diseases, relatively quick and inexpensive.
Limitations: Recall bias, selection bias.
5. Cohort Studies
Strengths: Can study multiple outcomes, good for establishing temporal relationships.
Limitations: Expensive, time-consuming, potential for loss to follow-up.
6. Randomized Controlled Trials
Strengths: High internal validity, can establish causality.
Limitations: Expensive, ethical constraints, may not be generalizable.
7. Existing Data
Strengths: Cost-effective, large datasets.
Limitations: Data may be outdated or incomplete, potential for misclassification.
