Out of any third-party CARS resource, UWorld comes the closest to the AAMC style. In particular, the way that most of the questions are written is very representative of the AAMC logic.
I highly recommend using it if you have access to it.
There’s one main drawback: the difficulty. UWorld passages are often very difficult, and on average you should expect your scores to be noticeably lower on UWorld than they would be on the AAMC. With my students, I often see a difference of 10-20%.
If you typically do fairly well on CARS, this isn’t a big deal. Just know that the UWorld questions are harder, and don’t put too much stock in your score.
On the other hand, if you typically struggle with CARS, then this lower score can become discouraging over time. You may score very low, much lower than you’re used to. If you find that you are able use the passages and not get overly invested in your score, then there’s no issue with this. But if it starts to drain your confidence too much, then you might want to find a different resource.
(Note: sometimes on forums people refer to UWorld as “UEarth.” So if you saw that and you were wondering if that’s the same thing as UWorld…it is.)
For the most part, the readings (meaning just the passage itself, not including the questions) are a good match with the AAMC. They have about the same distribution of subjects and styles of writing.
On average, I do think they’re a little more difficult than the AAMC readings, but not so much that it’s a problem.
One slight disadvantage is that it seems like UWorld writes the readings themselves—unlike the AAMC where the readings are drawn from actual published sources: books, journal articles, magazines, etc. I think this results in some UWorld passages that aren’t as logically sound as they should be. That makes them a little less accurate as a representation of the AAMC material.
The questions are where UWorld really shines. Unlike so many other resources, their questions are typically clear, unambiguous, and logical. This is a large part of why they’re so representative of the AAMC style.
Don’t get me wrong though: UWorld questions are often very difficult. And there’s a certain number of them that truly don’t make sense.
But on average, they’ve done a better job with their questions than any other resource I’ve seen. You don’t run into many of the ridiculous logical leaps or sloppily written questions that plague third-party resources.
And this is as it should be. As strange as some AAMC questions might seem on the surface, almost every single one of them has a relatively simple logical explanation once you’ve correctly understood it. (Trust me, I’ve looked at every AAMC CARS question probably hundreds of times.) The same is not true of most third-party CARS, but it is true—or at least more true—of UWorld.
Because UWorld questions are significantly more difficult than the AAMC, you will likely score much worse on them. I’ve often seen differences of 10-20% among my students. So take your UWorld scores with a grain of salt. I consider any score above 75% on UWorld to be very good. I see almost nobody scoring above 85% on UWorld, even among some of my students who get almost all of the AAMC questions correct.
When you review UWorld passages, it will show you the percentage of people who picked each answer. I recommend using these percentages to guide your review. Mostly, you should pay attention to the higher percentage questions that you missed (meaning questions where, say, at least 50-60% of people got the question right).
You’ll probably also see a number of lower percentage questions where maybe 30%, 20%, or even a lower percentage of people picked the right answer. Those questions are not worth your time to review carefully. They’re usually too difficult and don’t represent the AAMC style as accurately. You want to focus your attention more on the easier questions you missed, because those are going to be easier to improve upon.
The UWorld interface is as good as you could ask for. It looks like the real exam and has all the same features as the real exam.
You can create sets of passages with any number of questions you want, filter which type of passages you want to see, and do them timed or untimed. There’s also lot of other helpful features for reviewing the passages.
At the time I’m writing this, the cheapest UWorld plan is $219 for 90-day access, so it is a bit expensive. But for that price you do get access to the whole question bank of 1900+ questions, which includes the science sections. UWorld science content is also great, so I recommend purchasing it if you can.