# Biostats and Ethics (PHS), Start to Finish, in 3 Days

> Public Health Sciences for Step 1 in 3 days: decode First Aid pp. 256–277 on the First Aid Guide with the free HY Biostats PDF, then the Dirty Medicine ethics and Neil Randy biostats playlists, the FA Foundation Anki biostats and ethics decks, and 120 questions in blocks of 20. The last system before your revision week.

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## Questions this guide answers

- **How do I study biostatistics and ethics (PHS) for Step 1 in 3 days?** Do PHS right after cardio and before your revision week. Day 1: decode the biostatistics and epidemiology pages, First Aid pp. 256–267, on the First Aid Guide with the free HY Biostats PDF beside you. Day 2: ethics, communication and patient safety, pp. 267–277, then the Dirty Medicine ethics playlist, the Neil Randy biostats playlist and the FA Foundation Anki biostats deck. Day 3: the ethics deck, then 120 questions in tutor-mode blocks of 20, with every miss traced to its First Aid line. Go deeper on AMBOSS for biostats and ethics, because UWorld's coverage there is thin. Save the NBME Booster biostats and ethics cards for your revision phase.

## Page text

USMLE Vault · Step 1 · Biostats & Ethics
Biostats and Ethics (PHS), Start to Finish, in 3 Days
22 First Aid pages · 109 Anki cards · 3 days . For IMGs who just closed cardio: the last system before your revision week.
By Dr. Marish Asudani · Published 26 October 2026
How do I study biostatistics and ethics (PHS) for Step 1 in 3 days?
Do PHS right after cardio and before your revision week. Day 1: decode the biostatistics and epidemiology pages, First Aid pp. 256–267, on the First Aid Guide with the free HY Biostats PDF beside you. Day 2: ethics, communication and patient safety, pp. 267–277, then the Dirty Medicine ethics playlist, the Neil Randy biostats playlist and the FA Foundation Anki biostats deck. Day 3: the ethics deck, then 120 questions in tutor-mode blocks of 20, with every miss traced to its First Aid line. Go deeper on AMBOSS for biostats and ethics , because UWorld's coverage there is thin. Save the NBME Booster biostats and ethics cards for your revision phase.
Read this first. This plan is for roughly 10–12 hours a day . At 7–8 hours a day, the Vault schedule gives PHS 4 days; under 5 hours, 6 days. Keep the same order and stretch the days: Step 1 while working →
Biostats is the most reliably tested, most reliably neglected block on Step 1. IMGs do the same 2 things: memorise the formulas cold, then grind UWorld biostats questions. Both are wrong in the same way. Neither one teaches you the concept, and the vignette never announces which formula it wants. That's the entire trick of a biostats question.
Students who did this
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Ethics goes in the same 3 days for 1 reason: it's tested the same way. A scenario, and a judgement about what the scenario actually asks. My full reasoning, resource by resource: Biostatistics and Ethics →
Start here · before page 1
PHS has no micro or pharm. It has 2 PDFs.
Every other system starts with its organisms and drugs. PHS starts with the free HY Biostats PDF and the Biostats Workbook : the first stays open beside First Aid while you read, the second is worked examples for odds ratio, relative risk, ARR and NNT. Download both before Day 1.
The 2 PDFs
The High-Yield Biostats PDF → Every formula in 1 place. Open beside First Aid on Day 1, and again in your final week.
The Biostats Workbook → Worked examples: odds ratio, relative risk, ARR, NNT. Day 1 evening.
Both in the Vault University → Next to the Neil Randy PDF, the Mehlman HY Arrows and the rest of the free sheets
Open Public Health Sciences in the First Aid Guide → First Aid pp. 256–277, page by page, with the MCQs under every page.
Where this system sits
The order: easy systems first, cardio last, then PHS
Biostats and ethics come after cardio , as the last block of First Aid. Then your revision week, then NBME 27. Tap a system to open its guide.
1 Renal 6 days · the easy one, start here Open →
2 Respiratory 6 days · same method as renal Open →
Before it: Biochem nutrition, 1 day, right before GI · where it sits
3 GI 7 days Open →
4 Reproductive 7 days Open →
Before it: Biochem carb and lipid metabolism, 1 day, right before endo · where it sits
5 Endocrine 6 days Open →
6 Immunology 5 days Open →
Before it: Biochem cellular, molecular and amino acids, right before heme-onc · where it sits
7 Heme-onc 6 days Open →
8 MSK 6 days, no derm Open →
Before it: Dermatology, 3 days, after MSK · the derm block
9 Psychiatry 5 days Open →
Before it: Genetics and ANS, right before neuro · genetics
10 Neurology 7 days Open →
11 Cardiovascular 7 days · the last organ system Open →
12 Biostats & Ethics You are here 3 days · closes First Aid Open →
After it: the revision week, then NBME 27 · the revision week
The whole method, once: how to study any system → · the full order and your exam date: the Step 1 roadmap →
Biostats and ethics in 3 days, hour by hour
PHS runs the same order as every system ( how to study any system ): active reading on the First Aid Guide, then active application with videos, then active recall with the FA Foundation Anki, and only then questions. 2 things are different. There is no Mehlman step: the videos are the Dirty Medicine ethics playlist and the Neil Randy biostats playlist. And the questions go deeper on AMBOSS, not only UWorld.
▶ How to Do the PHS System (Biostats Ethics) 15 minutes. Watch it once, before Day 1. It's the video the Vault schedule gives you on day 1 of PHS.
Clock times assume an 11-hour day: 9 AM–1 PM, 2–6 PM and 7–10 PM, with lunch and dinner in the gaps. Shift the clock to your day. Keep the order.
Day 1 · Biostats and epidemiology: decode, don't memorise First Aid Guide pp. 256–267, the HY Biostats PDF open beside it
9–9:15 AM Watch How to Do the PHS System , the University walkthrough.
9:15 AM–1 PM pp. 256–259 · study designs, clinical trial phases, intention-to-treat, the 2×2 table, odds ratio vs relative risk, NNT, attack rate, Kaplan-Meier
2–6 PM pp. 260–263 · sensitivity, specificity, PPV and NPV, prevalence vs incidence, every bias, confounding, effect modification
7–9:30 PM pp. 264–267 · distributions, hypothesis testing, type I and II errors, power, confidence intervals, t-test, ANOVA, chi-square, correlation
9:30–10 PM The Biostats Workbook : odds ratio, relative risk, ARR, NNT, worked by hand.
Day 2 · Ethics reading, then the 2 playlists pp. 267–277, then active application, then the biostats deck
9 AM–1 PM pp. 267–272 · core principles, capacity, consent, minors, advance directives, surrogates, confidentiality, communication skills, challenging patient scenarios
2–4 PM pp. 273–277 · the rest of the scenarios, disabilities and interpreters, healthcare delivery, disease prevention, medical errors and patient safety
4–6 PM The Dirty Medicine ethics playlist , from the top, in order.
7–9 PM The Neil Randy biostats playlist . Pause before he answers and answer it yourself.
9–10 PM FA Foundation Anki · Biostats , 52 cards. Answer before you flip.
Day 3 · The ethics deck, then questions Unused · PHS only · tutor mode · blocks of 20
9–10 AM FA Foundation Anki · Ethics , 57 cards. Then any biostats cards that are due.
10 AM–1 PM Blocks 1–2 (Qs 1–40): solve both in tutor mode, log each score, then review every bookmark in First Aid.
2–6 PM Blocks 3–4 (Qs 41–80): solve both in tutor mode, log each score, then review every bookmark in First Aid.
7–10 PM Blocks 5–6 (Qs 81–120): solve both in tutor mode, log each score, then review every bookmark in First Aid.
This is the RPSR method, squeezed into 3 days. R ead = Day 1 and the Day 2 morning. P re-solve = the page MCQs, the 2 playlists and both decks. S olve and R eview = Day 3. Full method: The RPSR Method .
Want a day-by-day schedule that tells you exactly what to study next? The Vault builds it around your exam date, PHS included.
Build my schedule →
Day 1
Active reading — the biostats pages, decoded
Open the First Aid Guide → Public Health Sciences in the Vault ( what the First Aid Guide is ), with the HY Biostats PDF open beside it. Decode every page. Don't memorise it. Sensitivity and specificity are not 2 formulas to hold in your head: they are 2 different questions the exam asks about the same 2×2 table .
Open PHS in the First Aid Guide First Aid pp. 256–277, page by page: what each line means, the best video where a topic needs one, and 97 MCQs under the pages (as of October 2026). Opens straight into PHS.
Open PHS →
1
Read Focus On for the page, then the ELI5s. Explain each heading back in your own words. If you can't say which question a formula answers without writing it down, you haven't decoded it.
2
Read the actual First Aid page , with the HY Biostats PDF next to it. It should now read like a summary of something you already know.
3
Solve the Test Yourself MCQs on that page, in the same minute. Any miss → back to that heading before you turn the page.
Why this order: every biostats question is a concept wearing a number . Decode the concept first and the arithmetic becomes trivial. Do it the other way round and you get the arithmetic right on the wrong quantity.
Day 1 · pp. 256–267 · biostatistics and epidemiology (12 pages)
Pages Topic
256–257 Study designs, case-control vs cohort, clinical trial phases, intention-to-treat vs per-protocol, crossover
258–259 The 2×2 table, odds ratio vs relative risk, ARR, RRR, NNT, attack rate, Kaplan-Meier
260–261 Sensitivity, specificity, PPV, NPV, prevalence, incidence
262–263 Bias (Berkson, recall, attrition, lead-time, Hawthorne), confounding, effect modification
264–265 Distributions and skew, standard error, hypothesis testing, type I and II errors, power, p-values
266–267 Confidence intervals, t-test, ANOVA, chi-square, meta-analysis, correlation
Close the day with the Biostats Workbook : odds ratio, relative risk, ARR and NNT, worked by hand, the night you decoded them.
Day 2 morning
Active reading — ethics, communication and patient safety
Same First Aid Guide, same 3 steps, pp. 267–277. This half of First Aid is the ethics, the communication and the patient safety: read each page for what the scenario asks you to do , not for rules to recite.
Day 2 · pp. 267–277 · ethics, communication, patient safety (11 pages)
Pages Topic
267–269 Core ethical principles, decision-making capacity, informed consent, minors, advance directives, surrogates, confidentiality
270–271 Communication skills: delivering bad news, open-ended questions, motivational interviewing
272–273 Challenging patient scenarios: nonadherence, nondisclosure requests, gifts and conflicts of interest, an impaired colleague
274 Patients with disabilities, medical interpreters
275–276 Healthcare delivery, disease prevention, insurance and payment models, palliative care
277 Medical errors and patient safety, error analysis, burnout
🎬
A page still won't click? If the First Aid Guide page has a video, watch it first: the Guide puts the best video for the topic on the pages that need one. Still unclear? 1 backup video, for that topic only:
▶ Mehlman Medical · Biostatistics Short videos. 1 video for 1 topic.
▶ Mehlman Medical · Ethics For a principle that still won't land.
▶ Dirty Medicine · USMLE Communications Questions 25 minutes. For pp. 270–272.
Day 2 afternoon and evening
Active application — Dirty Medicine ethics, Neil Randy biostats
In every organ system, this step is Mehlman. In PHS it's 2 playlists , about 2 hours each on the Vault schedule . You understand the pages. Now learn how the exam asks them .
1
Dirty Medicine, ethics, first. It's a banger for your Step 1, Step 2 and Step 3 ethics: do it once and you're set for all 3. In order, from the top.
2
Neil Randy, biostats, second. Pause before he answers and answer it yourself. Anything that exposes a gap → open that First Aid Guide page and fix it the same day.
▶ Dirty Medicine · Ethics playlist Step 1, Step 2 and Step 3 ethics. Do it once.
▶ Neil Randy · Biostatistics USMLE playlist The long-form one. His Shorts come later, before your NBMEs.
Why: Neil Randy is the most slept-on channel on YouTube, and everyone knows him for biostats. Here you use him for exactly that. More on both channels: 5 channels = 0 paid courses →
Day 2 night → Day 3 morning
Active recall — FA Foundation Anki, biostats and ethics
The FA Foundation Anki is First Aid, page by page. PHS has 2 decks: Biostats · 52 cards and Ethics · 57 cards (as of October 2026). Most cards are a short scenario and a question , the same shape as the exam, and every card carries its First Aid page .
1
Biostats on Day 2 night, ethics on Day 3 morning. Answer before you flip. Recognising a line and pulling it out of memory are different skills.
2
Hesitate → open the page. Go to that page in the First Aid Guide , read the line plus a couple above and below, then return to the card.
…

## Source

USMLE Vault — https://usmlevault.com
Author: Dr. Marish Asudani

Updated: 2026-10-26