Is a referral Officer Performance Report (OPR) a career ender?

Vegas odds are not good but so much depends on the "what" and "how bad". These procedures have been established since my time, i.e. the draft, your opportunity to respond, etc. If it's being done, it's being done for a reason because the administrative overhead is much higher having to go through the process. The reporting senior wants to get it right because the process blowing up is a reflection of their performance. Make sure anything being said doesn't violate the reg on matters prohibited from the OPR. That said, besides the problem topics, there's still a decision tree which starts with a front end one of if you're worth keeping around and worth the extra investment. If not, minds are pretty much made up, then you either don't promote and let DOPMA rules push you out, or if they don't want to wait, administratively execute your departure. Tough road for all. Whatever the outcome, if you won't be around, do whatever it takes to retain "honorable conditions" on the DD-214 if you can. That paper and potential cloud follows you in ways that get painful at times.

Now if you get a chance for atonement and continue, then by the time you hit O-4 board, O-2 paper doesn't carry near the weight as to what you've been doing as an O-3, unless you wind up in the third crunch for which by then the board is looking for reasons to toss and they just found one. That should tell you what level your performance between now and then needs to be. It's like Soccer. Never give the referee a reason to toss you if you want to stay in the game.

Know I'm Navy but I sat a number of promotion boards and know the dynamic. All services have similarities. And I'm a soccer referee too.....

It is not NECESSARILY a career ender. I know at least one Officer whose senior rater opined that the Officer should be separated from service as a CPT who went on to be a BN CDR.

As CAPT Kevin B. states, that is way to bet. I would make contingency plans on that being the case.

Having said that, if you are going to get one, LT time is probably the "best" time to get one. There is an expectation that LT time is when you may not have figured the military out yet. I would absolutely take the opportunity to provide comments on the OER/OPR. Use it to EXPLAIN, but not JUSTIFY, any substandard performance, and demonstrate that you have learned from it. Alternately, you can fight it, but ONLY if you can point to material errors in relevant FACT. Remember, the report is by its nature subjective. If MAJ X says that you don't measure up to their expectations, that is an ASSESSMENT - which they can make. Attempting to rebut their assessment without reference to objective fact is a losing hand.

THEN ensure that the next 3+ are all ACOM (or whatever we call it today) to show that it was a fluke and not a true indicator of value of the officer. If the military is in a growing phase, as it is now, that may do the trick.

Sir, it sure isn't good although OPRs can be appealed, the writer still has to justify what ever He or She said. If they can't justify and document what they said then they have a problem. If a second evaluation official or one to endorse had a far different opinion and it was expressed on that same evaluation that may help. Its possible to of course make up for it following OPRs or if previous ones were ok or even better outstanding. Of course if the cost was high enough to get You passed over for promotion three times, Yes the career as an Officer would be over. I have seen officers that happened to and stayed in as enlisted men although at retirement they still retired at the Highest rank held which was their Officers rank. I hope some of what I said helps answer Your question.