Yes, for econ or PPE make sure you have Calc BC - it’s technically not absolutely required for PPE but it’s highly recommended. Plus some history APs would be useful imo. If you’re interested in both econ and philosophy, PPE may be the subject for you - you can drop the politics after the first year. An increasing number of other UK universities also now offer PPE; you can appky to up to four other UK universities on the same UCAS application.
If you go for straight philosophy at Cambridge no specific subjects are required at AP, but history a=is always a useful preparation.
Have a look at the Ox and Cam websites, specifically for the departments you’re looking at applying to as that will give you a better idea s to the course.
In retrospect we should have had S18 do a proper AP or (better) university level economics course over the summer before applying for PPE. Even though they said it didn’t matter that he hadn’t studied economics previously, in the interview that was his downfall. The economics questions were mathy but also required an ability to figure out issues like demand/supply curves and familiarity with the subject would have helped.
I think straight economics at Cambridge would be very hard to get into without that. However for philosophy it was a bit easier to bluff your way through the PPE interview - isn’t that the point of philosophy anyway? 
Note that most Oxford PPEists seem to drop economics and focus on pol/phil after the first year.
AP Economics is WAY below what is expected, so when they say “it’s not necessary to have studied economics” they don’t mean “AP Economics”, which is an easy intro course, but rather “it’s not necessary to master intermediate micro and macro economics theories and problems”, with the understanding you’ll have read and covered enough to understand the questions and profer answers. Oxbridge is all about independent reading and thinking so they assume taking a course isn’t necessary as long as you’re able to build a decent reading list and actually read the books, annotate them, grasp the concepts, do the exercises, etc.
Calculus is a given (it’s an 11th grade level course for kids planning to read Econ at Oxbridge.) Ideally you’ve had BC junior year and further maths senior year (linear algebra, MV calculus, calculus-based statistics and probability).
You should be able to comprehend the questions in the first chapters of this book even if you can’t produce any sort of answer.
https://www3.nd.edu/~esims1/gls_int_macro.pdf
For philosophy, you need to read philosophers and have a grasp of major movements in the history of ideas. The websites will give you an idea of what to read.
Here’s the syllabus for what British students are expected to master. The tests will actually test further reasoning/content than that.
http://www.cambridgeinternational.org/programmes-and-qualifications/cambridge-international-as-and-a-level-mathematics-further-9231/
http://www.cambridgeinternational.org/programmes-and-qualifications/cambridge-international-as-and-a-level-economics-9708/
http://www.aqa.org.uk/subjects/philosophy/as-and-a-level/philosophy-2175
If you go to an IB school I would take IB Econ in junior/11th grade year. It goes beyond both AP tests, even at the SL level. After taking it my D17 was able to easily get a 5 on both AP exams with no extra study.
To add to @MYOS1634’s very insightful post, the vast majority of candidates (23 of the 27 were from the UK, 2 from the US, 1 from the Middle East and 1 from New Zealand) that got an interview along with S18 had done further math. Almost none had done economics or philosophy at A-level. But their schools in the UK had mostly given them regular interview practice (typically one Oxbridge style rehearsal interview per week for the whole fall term) specific to the subject and presumably a reading list for philosophy and economics.
S18 was actually very competitive on the politics side (which is his obsession), as he was asked (and successfully answered) the extra part of the question that you only get if you answer the first bit successfully (he said only one of the others he knew got asked that part, and that person got an offer but was reassigned to another college). The philosophy part of interview went OK, but he just couldn’t figure out how to answer the economics question. He probably should have applied for His/Pol instead, but he only got a 3 in AP Euro in his sophomore year (his first exposure to AP question style with a hopeless teacher who didn’t cover the material properly), so that deterred him. Also PPE is more widely recognized, but correspondingly difficult to get a place. He might have had more success with SPS at Cambridge, but he wasn’t so keen on the breadth of that course in the first year and the likelihood of a conditional offer because of their minimum of 5 APs.
Sticking up for HisPol, which is actually harder to get a place in than PPE (fewer places & they don’t always fill them). Otherwise, I agree with everything:-)
Yes, I know HisPol is harder to get into. But at least he would have had a better idea about the content for the interview. However, given his AP Euro score, he should probably have picked SPS at Cambridge. The deterrent of a conditional offer based on this year’s APs loomed larger back then than it would do now.
Also worth noting that the admission stats by both subject and college are listed online. We didn’t realize until after his interview that he had applied to the most competitive college (Brasenose). He probably should have picked more strategically (even though the probability of a different outcome is likely to be quite low) rather than just concluding he liked that college because of its central location and good accommodation.
@Twoin18 @collegemom3717 I’m currently taking Calculus, but I’ll be doing BC senior year. Would you recommend that I take AP Stats as well? In addition, I’m going to be taking AP Econ senior year, and before senior year I’d have taken at least 5 APs. Should I take additional AP classes?
So do you want to apply for PPE at Oxford? Its a balancing act because you will potentially get a conditional offer that will include the relevant APs, so if you add Stats then you may have to get a 5 on that as well as BC and Econ. Only take APs you are confident you will get 5 in. Anything less than that will look worse than not having taken it at all.
Brasenose is a great college- great location & really nice people. The admissions tutors insist that you can’t be strategic on college choice, b/c of the way that Oxford does pooling before & during interview (v Cambridge, which does pooling after). The students think that is more true for some subjects than others- the more tightly the subject operates as a unit, the more true it is. PPE, b/c it cuts across 3 subjects is harder to guess. The other wild card is that the actual # of applicants by subject & college can swing pretty wildly year on year. Christ Church (aka Slytherin) has a big PPE rep.
One of the big factors in my son’s choice of college (he applied to and was accepted at Worcester) was the number of students in his area. He didn’t want to be one of a handful on the course. There’s a great group of mathmos at Worcester and they have 15 math students in his year (math, math&CS, math&stats, math&philosophy).
@collegemom3717 Would you recommend applying to one college, or should I let Oxford sort me and see if I was admitted?
@HazeGrey Would you know which college is easier to get into? For PPE? Or for any program that would correlate well for an eventual career in law?
@Twoin18 While I’d like to do PPE, it seems to be a bit difficult to get into with my current classes. Would you recommend any other majors (except English) for an eventual career in law?
@collegemom3717 A lot of other colleges have a list of their majors, (eg. georgetown) do you know of any place I can see all the possible majors for Oxford? I’ve been digging around, but haven’t found any. While I’m interested in PPE, I know that it may be hard to get into and I would like a major with business instead. @Twoin18 By the time I apply in my senior year, I would have taken 2 AP history classes, but quite possibly 3. Do you think that’ll be enough? Also-does it look better to have taken AP Euro instead of AP World? (Because I took AP world and might not know as much about British history) I also would prefer a non-conditional offer, my parents would probably push me towards a college here in that case, and I’d rather go back to Britain. (I used to live there when I was in elementary and I loved it) Is there any way I can ensure that it’s not conditional?
@collegemom3717 In addition, I looked up the podcasts on iTunes! Thank you so much for telling me about that-they’re really interesting and helpful.
@Twoin18 @collegemom3717 If I took classes at my local community college, not APs, but college level-would those be viewed favorably?
If you love the UK, you shouldn’t focus on Oxbridge and also explore other UK schools.
But study-abroad at American colleges is also a thing. Pretty much all of them would have multiple and extensive programs in the UK these days.
Also, is your final goal a JD? What citizenship/work permissions will you have?
@PurpleTitan While I do love the UK, I also value a good education, and so do my parents-they’re unwilling to let me go to a UK school if it’s not prestigious or academically rigorous. I would prefer to study at Oxford, espc. however, because when I visited it, I got the right kind of vibe from it-I felt I could fit in.It’s definitely my dream school. Although I might pursue law in the UK itself, there is a high chance I’d just do my undergrad from Oxford and then move back the the US for law school, but I don’t suppose it will matter too much because I want to do international law. That is, of course, if I was accepted into Oxford.
This is why I ask about citizenship/work permit issues.
If you are American, getting an LLB in the UK doesn’t make much sense.
BTW, you realize that there are other top-notch unis in the UK outside Oxbridge, right?
You need to be obsessive about a particular subject. To be honest it’s a bit late to be undecided now. The list of subjects is right there on the website https://www.ox.ac.uk/admissions/undergraduate/courses-listing?wssl=1
That obsession should be with an academic subject, for the sake of learning. Most UK students don’t do courses with any practical application. Law is unusual (but even there the people applying have been obsessed with becoming a lawyer for several years - my S18 said he could tell exactly who was applying for law when he was there, they were the ones in suits and carried themselves very differently). So does some aspect of (say) historical fiction fascinate you (English)? How about the American Civil War (History)? What would you love to spend 3 years studying? Saying you want to do “business” suggests this wouldn’t really be suitable for you.