Hygiene Atlas

Atlas · Plate XIX · Community Health and Research · 04

Research design

Study designs rank from systematic reviews and randomized controlled trials at the top to case reports and expert opinion at the bottom. Cohort studies follow exposure forward toward an outcome, and case-control studies start from the outcome and look back. Random assignment, blinding and control groups protect internal validity, and an IRB reviews human-subjects research.

High-yield facts · 9

  1. Experimental studies manipulate an independent variable with random assignment; quasi-experimental studies lack random assignment.T9
  2. Observational designs: cross-sectional (one time point), case-control (retrospective), cohort (prospective or retrospective).T9
  3. Double-blind: neither subjects nor examiners know who gets the treatment, controlling bias.T9
  4. A control group gets a placebo or standard care for comparison.T9
  5. Random sampling gives every member an equal chance; stratified sampling samples within subgroups; convenience sampling is the weakest.T9
  6. Internal validity: results reflect the treatment, not confounders. External validity: results generalize to other populations.T9
  7. The Belmont Report principles: respect for persons, beneficence, justice; an IRB reviews research with human subjects.T9
  8. PICO frames a clinical question: patient/problem, intervention, comparison, outcome.T9
  9. Systematic reviews and meta-analyses top the evidence pyramid; expert opinion is at the bottom.T9

Facts are written in our own words; each tag links to its source. Values marked "sources vary" differ between references, so check the one your program uses.