🔬 Clinical Research Variable Lab
Exercise Overview
In this interactive simulation, you will act as a Peer Reviewer to audit the methodology of four clinical scenarios. By analyzing research abstracts, you must identify the functional roles of variables and classify them into the correct mathematical scales.
Learning Objectives:- Role Identification: Distinguish between Independent Variables (IV) and Dependent Variables (DV).
- Measurement Classification: Categorize variables into Nominal, Ordinal, Interval, or Ratio scales.
Scenario 1: Hypertension Trial
"200 participants receive CardioFix or a placebo. Researchers measure Systolic BP (mmHg) and Improvement Status (Worsened, Same, Improved)."
| Variable | Role (IV/DV) | Measurement Level |
|---|---|---|
| Type of Medication |
Rationale: Categorical grouping (Nominal) that is being manipulated (IV). | |
| Systolic BP |
Rationale: Outcome (DV). Zero mmHg is a true zero point, so it is Ratio. |
Scenario 2: Sleep & Memory
"Researchers track Hours Slept and administer a Memory Test (0–100 score). They also record Biological Sex."
| Variable | Role (IV/DV) | Measurement Level |
|---|---|---|
| Memory Test Score |
Rationale: Outcome (DV). Standardized test scores usually lack a 'true zero', making it Interval. | |
| Hours Slept |
Rationale: Predictor (IV). Time has a true zero, making it Ratio. |
Scenario 3: Post-Op Pain Management
"Patients receive Morphine Dosage (0mg, 5mg, 10mg). Researchers record Pain Intensity (1=None to 10=Excruciating)."
| Variable | Role (IV/DV) | Measurement Level |
|---|---|---|
| Morphine Dosage |
Rationale: The treatment (IV). 0mg is a true absence, making it Ratio. | |
| Pain Intensity (1-10) |
Rationale: The outcome (DV). Ranks are clear, but distances are not equal, so Ordinal. |
Scenario 4: Genetics & Disease
"Study examines if BRCA1 Gene Presence (Yes/No) predicts the Age of Onset of cancer."
| Variable | Role (IV/DV) | Measurement Level |
|---|---|---|
| BRCA1 Presence |
Rationale: Categorical predictor (IV) with no order, making it Nominal. | |
| Age of Onset |
Rationale: The outcome (DV). Age measures time from birth (true zero), making it Ratio. |