NBME 9 to Step 2 CK
The oldest form still in circulation, and the one most likely to be read wrong.
NBME 9 prints about 5.5 points low. NBME 9 prints roughly 5.5 points low against the common scale, so the converter credits those points back before projecting. Your printed number does not change on screen. It is an old form and it fades quickly under recency weighting, but it is not worthless: a recent 9 still carries real signal.
NBME 9 conversion table
Printed score to projected Step 2 CK range, for a form taken in the last month. The range is about a 68% band: roughly two in three students land inside it, which is why it is a range and not a single number. Take the exam further out and the band widens.
| NBME 9 printed | Projected Step 2 CK | Midpoint | Percentile |
|---|---|---|---|
| 200 | 213 to 235 | 224 | 6th |
| 205 | 217 to 239 | 228 | 8th |
| 210 | 221 to 243 | 232 | 12th |
| 215 | 225 to 247 | 236 | 18th |
| 220 | 229 to 251 | 240 | 24th |
| 225 | 233 to 255 | 244 | 32nd |
| 230 | 237 to 259 | 248 | 42nd |
| 235 | 240 to 262 | 251 | 50th |
| 240 | 244 to 266 | 255 | 60th |
| 245 | 248 to 270 | 259 | 71st |
| 250 | 252 to 274 | 263 | 81st |
| 255 | 256 to 278 | 267 | 89th |
| 260 | 260 to 282 | 271 | 95th |
| 265 | 264 to 286 | 275 | 98th |
| 270 | 268 to 290 | 279 | 98th |
Rows shaded amber have a projected floor below the 218 pass line. Percentile is against LCME first-takers. Your printed score is never restated as a lower number: where a correction applies it lives inside the math, not on your report.
What NBME 9 actually predicted, for 114 students
The table above is the model. This one is the record. These are 114 students who posted a NBME 9 score and, later, the real Step 2 CK score that followed. Median NBME 9 was 236; their median real score was 260, a jump of +24 points.
| NBME 9 printed | Students | Median real Step 2 | Middle half landed |
|---|---|---|---|
| below 230 | 47 | 252 | 248 to 261 |
| 230 to 239 | 21 | 257 | 254 to 262 |
| 240 to 249 | 15 | 263 | 258 to 268 |
| 250 to 259 | 21 | 268 | 263 to 270 |
| 260 and up | 10 | 270 | 268 to 273 |
Self-reported scores posted to public forums, paired per student. People who do well post more often than people who do not, so treat these as an optimistic ceiling rather than a population average. The middle-half column is the interquartile range: a quarter of students in that band finished below it and a quarter above.
How the projection works
Three steps, and the constants are published rather than described. First the printed score is put on the common scale: NBME 9 gains 5.5 points inside the math. Then it is shrunk toward the population mean of 250 with a slope of 0.79, which is what stops a single high form from projecting a fantasy. Then 9 points are added for the measured gain from practice form to real exam.
Fit on 258 real posted score reports and tested blind on 32 it had never seen: average miss 4.1 points, bias statistically zero. Reddit posters skew toward good news, so treat the range as honest rather than generous. Full methodology, including where the model stops being trustworthy.
Questions
- Is NBME 9 still worth taking?
- It is worth counting if you already took it. As a form to sit down and take now, prefer a newer one: 9 is old, it fades fast under recency weighting, and the correction it needs is a sign it sits slightly off the modern scale.
- Why does NBME 9 print low?
- It was equated in an older era against a different cohort. Fit on 160 students and 1,043 dated forms with person and timing controls, form 9 reads about 5.5 points below where the same student lands on the modern scale, so the model credits that back.
- How much does the date I took it matter?
- A lot, and more than most converters admit. Forms are weighted by recency with a roughly 21 day half-life, and the width of the projected range depends on how far out your exam is. A form from three months ago tells you much less than one from last week.