Hypothesis Testing: Primary goal is to test hypotheses.
Types of Experimental Studies
Randomized Controlled Trials (RCT)
Field Trials
Community Trials
Clinical Trials
Randomized Controlled Trials (RCT)
Gold Standard: Considered the gold standard for clinical research.
Double-Blind: Both the participants and investigators do not know who is in the control or experimental group.
Ethical Issues: Discusses whether to conduct studies on animals or humans, ensuring ethical considerations.
Prospective: Studies that move forward in time and look for outcomes.
Dropouts: Participants who leave the study are not excluded from the study.
Application: Used to evaluate new programs or therapies by randomizing participants into different groups.
Natural Experiments
Characteristics: Researchers do not have control over the allocation of subjects. Examples include John Snow’s study on cholera, and studies involving migratory populations, religious groups, or survivors of natural or nuclear disasters.
Examples: Bhopal Gas Tragedy, Chernobyl nuclear disaster.
Population: Studies can be performed on specific populations affected by external events.
Designing Experimental Studies
Protocol: Create a detailed plan before starting the study including objectives, population, and treatments.
Target Population vs Experimental Population: The target is the larger group, while the experimental is the subset being directly studied.
Control Group: Used to provide alternative explanations for results.
Randomization: Assign participants randomly to experimental or control groups to remove bias and confounding factors.
Importance of Randomization
Comparison: Ensures groups are comparable by distributing characteristics equally between groups.
Avoids Bias: Minimizes selection bias and confounding factors, providing each participant an equal chance of being in any group.
RCT Methodology
Manipulation and Intervention: Apply a treatment or remove a causative factor from one group and observe the outcomes.
Follow-Up: Regularly monitor both experimental and control groups over time to collect data and analyze results.
Cross-Over Design: Participants may switch from control to experimental group and vice versa to eliminate carry-over effects.
Intent-to-Treat Analysis: Includes dropouts in the final analysis to maintain the study's integrity.
Analyzing Results
Positive and Negative Effects: Track both beneficial and adverse outcomes.
Validity: Randomization increases the internal validity of the study's conclusions.
Applications
Health Services Research: Validation of new health services and interventions.
Etiological Agents Trials: Confirming the causative agents of diseases.