WEEK 7 CROSS-SECTIONAL & COHORT STUDY

Definition: Researchers observe subjects in their natural environment without intervention.
Types: Includes cohort studies, case-control studies, and cross-sectional studies.
Key Point: They can suggest correlations but do not establish definitive cause-and-effect relationships.

Definition: Researchers conduct controlled tests where they manipulate one or more variables.
Goal: Aim to establish a cause-and-effect relationship between variables.
Key Point: Variables are controlled to isolate effects and determine causal relationships.

Observational Studies: No manipulation of variables; record occurrences naturally.
Experimental Studies: Involves manipulation of variables to test outcomes.

Definition: Captures data at a single point in time among participants.
Purpose: Often used to assess prevalence of a condition or disease in a population.
Nature: Descriptive and can identify associations but cannot establish causality.
Example: Comparing prevalence of stress levels based on seating position in a classroom.
Limitations: No follow-up or temporality, hence limited in drawing causal conclusions.

Definition: Follows a group of people over time to assess changes and outcomes.
Nature: Data can be recorded prospectively (future) or retrospectively (past).
Purpose: Useful for studying incidence and causes of diseases.
Causality: It can provide evidence for causality as exposure is recorded before outcomes.
Example: Investigating health outcomes in individuals with different exposure statuses (e.g., comorbid health conditions).

Clinical Interventions: RCTs (Randomized Controlled Trials) are rated highest.
Cohort Studies: Represent significant evidence for prognosis and causality, placed just below RCTs.
Importance: Understanding the evidence hierarchy is essential for program/policy applications.

Research Question: Are people at the front of a classroom more stressed than those at the back?
Null Hypothesis: No significant difference in perceived stress levels based on seating position.
- H0: No difference between perceived stress of students sitting at the front and back.
Methodology: Use a stress assessment tool (e.g., Stress-o-meter) to measure stress levels.
Statistical Analysis: Use t-tests to compare means of two groups (front vs. back).

Validity/Reliability: Stress measures may lack established validity.
Self-Report Limitations: Issues such as recall bias or social desirability factor into results.
Temporality: Cross-sectional studies represent one point in time; cannot infer causality.