Epidemiology Formulas & Interpretation Cheat Sheet — Complete Reference Guide
🩺 THE REFERENCE EVERY HEALTH PROFESSIONAL WISHES THEY HAD ON DAY ONE.
You are in the middle of writing a report. You need the formula for secondary attack rate. You know you learned it. You know it exists. But right now, at this moment, with a deadline in 20 minutes — you cannot find it.
So you open five browser tabs. You dig through your old lecture slides. You check three different textbooks. Forty minutes later, you have your answer.
That is forty minutes you will never get back.
This cheat sheet exists to end that problem — permanently.
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📘 WHAT IS THIS PRODUCT?
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The Epidemiology Formulas & Interpretation Cheat Sheet is an 18-page, beautifully designed PDF reference guide covering every essential formula, measure, and interpretation guide you need in clinical medicine, public health, research, and epidemiology practice.
It was written by a practicing physician-epidemiologist — not a textbook committee — which means every formula comes with the real-world context you actually need to use it correctly.
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📋 WHAT YOU WILL FIND INSIDE
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✅ SECTION 1 — Measures of Disease Frequency
Cumulative Incidence · Incidence Rate · Point & Period Prevalence · The Prevalence–Incidence Relationship · Case Fatality Rate · Maternal Mortality Ratio · Infant Mortality Rate
→ Every formula includes the full symbol legend, interpretation guide, and a worked numerical example.
✅ SECTION 2 — Measures of Association
Relative Risk (RR) · Odds Ratio (OR) · Attributable Risk (AR) · Population Attributable Risk (PAR) · Number Needed to Treat (NNT)
→ Complete 2×2 table reference included. Know exactly which measure to use, when, and why.
✅ SECTION 3 — Screening & Diagnostic Test Statistics
Sensitivity · Specificity · Positive Predictive Value (PPV) · Negative Predictive Value (NPV) · Likelihood Ratios (LR+ and LR−)
→ Includes the SnNout/SpPin clinical mnemonics and the base-rate fallacy explained clearly.
✅ SECTION 4 — Outbreak Investigation
Attack Rate · Secondary Attack Rate (SAR) · Basic Reproduction Number (R₀) · Herd Immunity Threshold (HIT)
→ Directly applicable to field outbreak investigations and surveillance reporting.
✅ SECTION 5 — Demographic & Vital Statistics
Crude Birth Rate · Crude Death Rate · Age-Specific Death Rate · Total Fertility Rate
→ Essential for annual health reporting, ministry submissions, and population health assessments.
✅ SECTION 6 — Vaccination & Immunity Metrics
Vaccine Efficacy (VE) · Vaccine Effectiveness · Vaccination Coverage
→ Distinguish between trial efficacy and real-world effectiveness. Know your coverage targets.
✅ SECTION 7 — Statistical Concepts
95% Confidence Intervals · Sample Size Formula · Statistical Test Selection Guide (9 scenarios)
→ Know which test to use for which situation — t-test, chi-square, Fisher's exact, logistic regression, Cox regression, and more.
✅ SECTION 8 — Study Design & Bias Reference
Evidence Hierarchy (7 levels) · 11 Bias Types with definitions and mitigation strategies
→ Instantly recognise selection bias, recall bias, confounding, effect modification, survivorship bias, and publication bias.
✅ QUICK REFERENCE CARD
All 26 core formulas in a single compact table — the page you will keep open permanently.
✅ INTERPRETATION DECISION TREES
How to interpret RR/OR values · How to interpret Likelihood Ratios · How to interpret p-values
→ Not just the formula — the clinical language to explain what it means.
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💡 WHO IS THIS FOR?
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→ Medical students preparing for exams or clinical rotations
→ Residents and junior doctors who need rapid formula recall
→ Epidemiologists and public health officers writing surveillance reports
→ Health managers and DSP officers preparing ministry submissions
→ Researchers designing studies or interpreting results
→ Nurses and paramedical staff pursuing academic qualifications
→ MPH and DrPH students tired of hunting through 600-page textbooks
→ Anyone who has ever Googled "what is the difference between sensitivity and PPV" at 11pm
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🏅 WHY THIS IS DIFFERENT FROM FREE RESOURCES
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Free cheat sheets give you formulas.
This gives you formulas + interpretation + clinical meaning + worked examples + decision trees.
Free resources are generic.
This was written by a practicing physician-epidemiologist who uses these formulas in real disease surveillance, outbreak response, and ministry reporting — not someone who compiled a Wikipedia list.
Free resources are scattered across 20 tabs.
This is one document. 18 pages. Everything in one place. Open it, find it, use it, close it.
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⚡ WHAT YOU GET INSTANTLY AFTER PURCHASE
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📄 1 professionally designed PDF (18 pages, print-ready)
🖨️ Print it and keep it on your desk
💻 Save it on your laptop for offline access
📱 Open it on your phone during rounds, fieldwork, or exams
No subscription. No login. No updates required. One purchase, yours forever.
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✍️ ABOUT THE AUTHOR
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Dr. Oussama Wail Bouhentala is a physician-epidemiologist and Head of the Prevention Service at DSP Biskra, Algeria, with an academic affiliation at the University of Biskra. He publishes practical professional tools under Bow Team Publications — resources built from daily public health practice, not theoretical compilation.
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