After reading the charting outcomes website, I am confused about the average step 1 score for successful ortho candidates. Is 230 the average for accepted U.S. applicants or for all U.S. applicants including those who were not successful. Any clarification would be helpful.

I read it as mean of all applicants as there are more applicants that there are positions available.

the average step I score for US seniors ortho is 232-235 for matriculants and it is lower (extrapolated from the data= 215) for those that did not matriculate.

However, that document was created so that we could have a general idea of where applicants stood. Because for decades medical students have been hearing "this 'specialty' is soo competitive... you shouldn't apply if you do not have at least a 230" but the message intended by publishing this data is to help show that there were for instance, "76 applicants with scores in the range of 210-220 and yes 22 didn't match but 54 of them did"

It is intended as a birds eye view; the administrators did not want students to read too much into the actual numbers.