MS2 to MS4: When to Lock In Clerkships That Matter Most for Match

It is January of MS2. Step 1 is looming, admin just emailed “Preliminary MS3 schedules will be released next month,” and your classmates are already whispering about “getting medicine early” and “saving surgery for letters.” You are still trying to remember the coag cascade, and now you are expected to engineer a clinical schedule that will decide your Match.

Here is the reality: when you do each clerkship matters. A lot. For letters. For shelf scores. For away rotations. For interview season. You do not need a perfect schedule. You do need a deliberate one.

I am going to walk you, chronologically, from mid‑MS2 through MS4. At each point: what you should already have done, what you need to lock in now, and what is actually a bad idea even though everyone on your GroupMe swears it is genius.

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MS2: The Year Before – Laying the Tracks

January–March of MS2: Big‑Picture Decisions

At this point you should:

• Have a short list of target specialties (2–3 realistic options, even if one is a “reach”).
• Know your school’s core clerkship blocks and how scheduling works:
  • Lottery? Priority points? Dean‑assigned?
  • Fixed sequence or flexible blocks?
  • Required sub‑I timing rules?
• Understand Step 1 timing relative to your clerkship start.

This is the planning phase, not the micromanaging‑every‑block phase. Your key decision now is: what should be early in MS3, and what absolutely must be early MS4?

For competitive specialties (derm, ortho, ENT, plastics, neurosurgery, ophtho), the timeline is harsh. You need:

• An early exposure rotation in MS3 (even if only 2–4 weeks).
• Strong performance and usually one letter by late MS3.
• An acting internship or away in early MS4 before ERAS.

For more “standard” specialties (IM, peds, EM, gen surg, psych, OB/GYN, FM), the key is to align:

1. The clerkships that will generate your most important letters.
2. The clerkships that will prepare you for Step 2 CK.
3. The sub‑I(s) that will sit before September of MS4.

At this point, actually do this:

• Open a blank 18‑month calendar (March MS2 → September MS4).
• Block out:
  • Step 1 dedicated.
  • Start and end of MS3 year.
  • School‑mandated clerkship blocks (Core IM, Surgery, OB/GYN, etc.).
• Mark your target specialty in bold next to the most relevant clerkships.

You are not locking anything yet. You are understanding constraints.

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April–June of MS2: Pre‑Clerkship Positioning and Priority Choices

This is when many schools ask for clerkship sequence preferences.

At this point you should:

• Have met with:
  • Your academic advisor.
  • At least one faculty member in your potential specialty.
• Have a ranked preference list for:
  • What you want in the first 3–4 blocks of MS3.
  • What you need in the final 3–4 blocks of MS3.

The usual “good” priorities:

1. Medicine in the first half of MS3
   • It underpins almost every shelf and Step 2.
   • It is a core letter source for IM, subspecialties, EM, neurology, even radiology.
2. Your likely specialty’s core rotation before winter break of MS3
   • So you can:
     • Decide if you actually like it.
     • Get at least one letter before ERAS opens the next year.
3. Avoid your target specialty as the very last core clerkship
   • You lose flexibility for:
     • Repeating exposure.
     • Doing an early sub‑I.
     • Collecting letters in time.

Bad ideas I see too often:

• “I will save medicine for last so I am best prepared.”
  Translation: you delay your strongest letter and Step 2 prep. This hurts.
• “I will do EM in January of MS4; letters will still be fine.”
  For EM, this is often too late. SLOEs are expected early.

Here is a quick snapshot of which clerkships matter most for which Matches:

Target Specialty	High-Impact Clerkships	Ideal Timing
Internal Medicine	IM, Sub-I in IM	IM early-mid MS3, Sub-I early MS4
General Surgery	Surgery, SICU, Surg Sub-I	Surgery early-mid MS3, Sub-I early MS4
EM	EM, IM, Surgery	EM late MS3 or very early MS4
OB/GYN	OB/GYN, Surgery, OB Sub-I	OB/GYN mid MS3, Sub-I early MS4
Pediatrics	Peds, IM, Peds Sub-I	Peds mid MS3, Sub-I early MS4

If your school is about to run the clerkship lottery, your job this month: submit a ranked sequence that puts your likely specialty and medicine on the earlier side of MS3 without stacking them together in Block 1.

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MS3: The Core Clerkship Year – Execution and Letters

Now the timing really starts to matter. MS3 is not just “do well.” It is “do well at the right times so your MS4 schedule has power.”

Month 1–2 of MS3: Your First Core Clerkship

At this point you should:

• Treat your first block as skill building, not your main letter source.
• Focus on:
  • Learning how to preround, write notes, present succinctly.
  • Building stamina for full clinical days.
  • Figuring out your school’s evaluation culture.

If your first clerkship is your target specialty, do not panic. It is survivable. But you must be deliberate:

• Identify 1–2 attendings early.
• Tell them directly by week 2: “I am strongly interested in [X]; I would value feedback on how to be a strong applicant.”
• Ask for the letter before the end of the rotation, even if you hold the ERAS upload until later.

What you should not be doing in the first two months: rearranging your entire schedule every week. Get the lay of the land, then adjust.

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Month 3–6 of MS3: Peak Core Clerkship Blocks

For most students, this is where medicine, surgery, OB/GYN, peds, or psych land. This middle stretch is where you lock in:

• Your first strong clinical letter.
• A realistic sense of what specialty actually fits you.
• The foundation for Step 2 CK.

At this point you should:

1. Identify 2–3 potential letter‑generating rotations.
   Examples:
   • IM for the IM, cards, GI, heme/onc hopeful.
   • Surgery for surgery, anesthesia, EM hopefuls.
   • OB/GYN for OB, REI hopefuls.
2. Decide who you want letters from by Week 2–3 of a given clerkship, not Week 6.
3. Start mapping forward into MS4:
   • When could you reasonably do a sub‑I?
   • When do your school’s “audition” rotations typically run?
   • When is your Step 2 CK testing window?

For EM specifically, by mid‑MS3 you need to know:

• When your home EM rotation runs.
• When you could schedule away EM rotations (usually May–August between MS3 and MS4 for the old calendar; check your school’s specifics).

This is the period to lock in sub‑I windows with your registrar if your school opens sign‑ups this early. The best blocks for a sub‑I that matters for Match:

• June–August of MS4 for most specialties.
• Equivalent early blocks in whatever calendar your school uses so letters are in by September.

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Late MS3 (Last 2–3 Clerkships): Transition to Application Mode

By now you should:

• Have at least one strong letter from a core clerkship.
• Know your actual target specialty (not the fantasy one from M1).
• Have a provisional MS4 schedule drafted.

At this point you should lock in:

1. At least one sub‑I or acting internship in your target field in the first 3 blocks of MS4.
2. For competitive fields or if your home program is weak:
   • One away rotation in your specialty (via VSLO/VSAS).
3. The timing of any Step 2 CK dedicated period.

Here is where sequencing of late MS3 and early MS4 matters:

• You do not want a high‑stakes sub‑I in your very first MS4 block if you finished MS3 totally burned out and plan to take Step 2 right before. Recipe for underperforming.
• You do want your key specialty rotation(s) to finish in time to:
  • Ask for letters by July.
  • Have letters uploaded by September.

To visualize sub‑I and away rotation pressure points:

Peak Months for High-Stakes Rotations

Category	Value
May	30
June	70
July	90
August	80
September	40

Where the higher bars are, competition for those spots at your home and away programs spikes. You need to reserve them months earlier.

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The MS3 → MS4 Bridge: Spring and Early Summer

This is where a lot of students either set themselves up beautifully or quietly wreck their application.

March–April of MS3: Finalize MS4 Skeleton

At this point you should have:

• Draft ERAS specialty choice(s).
• A rank order of:
  • Where you want to do your sub‑I.
  • Whether you need 0, 1, or 2 aways.
• A target Step 2 CK month.

Now you lock in the structure of MS4, even if electives are not all chosen yet.

General MS4 Structure That Works

Months relative to ERAS opening (assume ERAS opens June, apps submitted September; shift as needed):

• Block 1–3 (Mar–May or early MS4):
  • One sub‑I in your specialty or closely related field.
  • Possibly one away if necessary and feasible.
  • Step 2 CK somewhere in this window.
• Block 4–5 (Jun–Jul):
  • Second sub‑I or away rotation.
  • A lighter or non‑malignant elective if Step 2 is late.
• Block 6–8 (Aug–Oct):
  • Interview‑friendly electives, research, or light consult electives.
  • No high‑stakes required rotations here if you can avoid it.

Bad structure patterns I see:

• Two back‑to‑back brutal sub‑Is leading straight into ERAS submission and interviews. Burnout plus mediocre performance.
• Saving the only sub‑I in your field for September or October of MS4. Letters will not arrive in time to help.

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May–July (Early MS4): Execute on Sub‑I and Aways

This is when you are on stage.

At this point you should:

• Be on your first sub‑I or away if you are applying to:
  • EM
  • Ortho
  • Neurosurgery
  • ENT
  • Urology
  • Derm
  • Any other field where “audition” culture is strong
• Or at minimum on a high‑impact home sub‑I (IM, surgery, peds, OB) if you are applying in those.

Clerkships that matter most now:

• Sub‑I in your chosen specialty (or closest analog if your school lacks it).
• EM rotations that give you a SLOE (for EM).
• Medicine sub‑I (even if not going into IM, this letter carries weight broadly).

If you have not secured these by May, you are late. Not doomed, but you will have fewer options. Call coordinators. Ask about waitlists. Involve your dean’s office.

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MS4 Application Season: Lock‑In vs Flexibility

Once you hit late summer of MS4, you are no longer “planning” clerkships to help you match this cycle. You are selecting what will keep you sane and consistent through interviews.

August–October of MS4: Interview‑Season Scheduling

At this point you should:

• Have core letters submitted or pending.
• Have ERAS ready or submitted.
• Be entering the interview invitation phase.

The question becomes: what types of clerkships do you schedule now so you do not torpedo interviews?

Good choices:

• Light electives with flexible hours (radiology, path, some consult services).
• Research blocks.
• Teaching electives.
• Pre‑residency “boot camp” later in the spring, closer to graduation, not now.

Bad choices:

• An ICU month during peak interview season if you have any choice.
• A mandatory OB nights block when you expect 3–4 interviews a week.
• Another high‑stakes sub‑I that no longer improves your application but can create bad evals.

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Putting It All Together – Example Timelines

Let me give you concrete, reality‑based examples. These are not perfect schedules. They are reasonable.

Example 1: MS2 → MS4 for a Student Targeting Internal Medicine

Late MS2

At this point you should:

• Request:
  • Early or mid‑MS3 Medicine (Block 2–4).
  • Surgery and OB/GYN not both in the first 2 blocks.
• Plan:
  • Step 1 just before MS3.
  • Step 2 for early MS4 (May–June).

MS3

• Block 1: Psych (learn basic inpatient flow with lower intensity).
• Block 2–3: Internal Medicine (focus on performance and potential letter).
• Block 4: Surgery.
• Block 5–6: Peds, OB/GYN.
• Block 7: Family Med.

During IM block you:

• Identify a ward attending + subspecialist (cards, heme/onc) for letters.
• Ask them for letters by the final week.

MS3 → MS4 Bridge

• Lock in:
  • IM Sub‑I for May or June of MS4.
  • A second sub‑I in a subspecialty or another strong medicine team for July.
• Schedule Step 2:
  • Late June, after first IM sub‑I, using that as prep.

Early MS4

• May: IM Sub‑I (letter).
• June: Step 2 + lighter elective (ID consult, cards consult).
• July: Second IM‑related sub‑I if needed, or research.

By August, you have:

• 2–3 strong IM letters.
• Step 2 CK score back.
• No high‑stakes rotations during interview months.

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Example 2: MS2 → MS4 for a Student Targeting EM

Late MS2

At this point you should:

• Confirm:
  • When your home EM rotation runs.
  • Whether your school mandates it in MS3 or MS4.
• Request:
  • Medicine early/mid MS3.
  • Surgery early/mid MS3.

MS3

• Block 1: Peds.
• Block 2: Medicine (letter).
• Block 3: Surgery (letter option).
• Block 4: OB/GYN.
• Block 5: Psych.
• Block 6: Family Med.
• Block 7: Home EM rotation (if allowed in MS3).

During home EM, you:

• Aim for a home SLOE.
• Decide which regions/programs you want for away EM.

MS3 → MS4 Bridge

You lock in:

• One away EM rotation in June.
• One away EM rotation in July.
• Step 2 CK in early August.

Clerkships that matter most here:

• Home EM + 1–2 away EM = your SLOE set.
• Medicine and Surgery for general credibility and possible backup letters.

Inside that EM‑focused sequence, you maintain one rule: no step exam the week after finishing a 28‑day night‑heavy EM rotation. You give yourself at least a 1–2 week buffer with a lighter elective.

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Example 3: Quick Visual of Your 3‑Year Arc

Sometimes a simple visual helps you see where decisions stack. Here is a high‑level MS2 → MS4 structure:

MS2 to MS4 Clerkship Planning Timeline

Period	Event
MS2 - Jan-Mar MS2	Identify target specialties, learn scheduling rules
MS2 - Apr-Jun MS2	Submit clerkship preferences, plan Step 1 window
MS3 - Early MS3	First 2-3 cores, skill building, not main letters
MS3 - Mid MS3	Medicine and target specialty cores, secure first letters
MS3 - Late MS3	Final cores, decide specialty, lock MS4 sub-I blocks
MS4 - Early MS4	Sub-I and away rotations, Step 2 CK
MS4 - Mid MS4	Application submission, lighter electives for interviews
MS4 - Late MS4	Boot camps, gaps, graduation prep

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The Priority Hierarchy: What to Lock In When

To keep this from turning into white noise, here is the hierarchy I would use, in order, when you are forced to choose what to optimize.

At each phase, ask: What is the single most time‑sensitive clerkship decision right now?

• Late MS2:

  • 1. Medicine not last. Ideally early‑mid MS3.
  • 2. Your probable specialty’s core not last.
  • 3. Do not stack 2 brutal cores in Block 1 and 2 back‑to‑back.

• Early–Mid MS3:

  • 1. Identify and secure letter writers on medicine and target specialty cores.
  • 2. Make sure your target specialty core is done by winter of MS3.
  • 3. Reserve early MS4 blocks for sub‑I in your chosen field.

• Late MS3:

  • 1. Finalize at least one early‑MS4 sub‑I.
  • 2. Apply for away rotations if needed (VSLO/VSAS).
  • 3. Set an actual test date range for Step 2 CK.

• Early MS4:

  • 1. Perform at a high level on sub‑Is and aways (these are your Match‑critical clerkships).
  • 2. Get letters requested before the last week of each rotation.
  • 3. Keep Step 2 from being an afterthought crammed between 2 sub‑Is.

• Mid MS4 (interview season):

  • 1. Protect time and energy with lighter electives.
  • 2. Avoid adding new high‑stakes clerkships that cannot improve this cycle’s application.

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What You Should Do Today

You are somewhere on this timeline right now. MS2, MS3, or early MS4.

Here is your immediate, concrete step:

Open your school’s rotation calendar and your transcript. Write down, in three columns:

1. Clerkships you have already completed.
2. Clerkships scheduled but not yet done.
3. Open blocks/elective time.

Then, next to each open block, write one thing:

• “Sub‑I,” “Away EM,” “Light elective,” or “Step 2 prep.”

Look for the first 2–3 open blocks in MS4 and label them with something that will directly support your Match: a sub‑I in your specialty, an away that yields a key letter, or a well‑timed Step 2 period.

Do not close the calendar until those early MS4 blocks are intentionally labeled. That is how you stop drifting through clerkships and start using them.