UWSA 1 to Step 2 CK
The UWorld self-assessment that sits closest to the NBME scale.
UWSA 1 carries no correction. UWSA 1 reads roughly on scale against the NBMEs, so no correction is applied. That makes it more directly comparable to an NBME than UWSA 2 is, and it is the UWorld form least likely to mislead you in either direction.
UWSA 1 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.
| UWSA 1 printed | Projected Step 2 CK | Midpoint | Percentile |
|---|---|---|---|
| 200 | 209 to 231 | 220 | 4th |
| 205 | 212 to 234 | 223 | 5th |
| 210 | 216 to 238 | 227 | 8th |
| 215 | 220 to 242 | 231 | 11th |
| 220 | 224 to 246 | 235 | 16th |
| 225 | 228 to 250 | 239 | 22nd |
| 230 | 232 to 254 | 243 | 30th |
| 235 | 236 to 258 | 247 | 39th |
| 240 | 240 to 262 | 251 | 50th |
| 245 | 244 to 266 | 255 | 60th |
| 250 | 248 to 270 | 259 | 71st |
| 255 | 252 to 274 | 263 | 81st |
| 260 | 256 to 278 | 267 | 89th |
| 265 | 260 to 282 | 271 | 95th |
| 270 | 264 to 286 | 275 | 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 UWSA 1 actually predicted, for 108 students
The table above is the model. This one is the record. These are 108 students who posted a UWSA 1 score and, later, the real Step 2 CK score that followed. Median UWSA 1 was 246; their median real score was 260, a jump of +13.5 points.
| UWSA 1 printed | Students | Median real Step 2 | Middle half landed |
|---|---|---|---|
| below 230 | 25 | 251 | 246 to 256 |
| 230 to 239 | 10 | 256 | 250 to 260 |
| 240 to 249 | 29 | 261 | 256 to 267 |
| 250 to 259 | 18 | 265 | 258 to 269 |
| 260 and up | 26 | 270 | 264 to 272 |
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. 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 UWSA 1 accurate for Step 2 CK?
- It sits roughly on the NBME scale, so it enters the projection without a correction. Like any single form it is one noisy read: the projection reports a range, and the range narrows as your exam approaches and as you add more recent forms.
- UWSA 1 or UWSA 2, which should I trust?
- UWSA 1 sits on scale; UWSA 2 prints about 4.8 points hot and is translated down before blending. Neither is wrong, they are just on slightly different scales, and the converter handles the difference so you do not have to.
- 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.