Learn to Count Quantitative Methods
Quantitative methods count and measure. Surveys, experiments, observational studies producing numbers. Statistics turn these numbers into findings. Large samples give statistical power; small samples have more uncertainty. Quantitative research scales where qualitative cant.
The Core Idea
Common designs: (1) Randomized controlled trial (RCT) — randomly assign groups, compare outcomes. Gold standard. (2) Observational study — measure without intervening. (3) Cross-sectional — one moment in time. (4) Longitudinal — over time. Each has strengths and weaknesses.
Examples
Drug trials: RCT, randomly give drug or placebo, compare. Census: observational, cross-sectional. Framingham Heart Study: observational, longitudinal, 75+ years, changed heart disease science. Each produced thousands of papers and policies.
Whats the gold standard research design?
Going Deeper
Sample size matters. Rule of thumb: for comparing groups, aim for 30+ per group minimum. For surveys of populations, 400+ gives 5% margin of error. Underpowered studies (too few participants) produce unreliable results. Pre-calculating needed sample size is crucial.
Calculate Margin
Design One
Longitudinal study means:
Is 10 participants usually enough?
Want to keep learning?
Sign up for free to access the full curriculum — all subjects, all ages.
Start Learning Free