<p>for people who have taken both tests, which one do you think is harder: AP Biology or the USABO open exam?</p>
<p>These are very different tests, so a good comparison is hard. The USABO open is much shorter than the AP test, which I suppose makes it easier. The USABO open requires a much deeper level of factual knowledge, while it doesn't have the 'conceptual understanding' type questions AP has.</p>
<p>Of course, as you move on to the higher levels of USABO, it gets far harder than AP.</p>
<p>If you're taking AP this year, I suggest you go ahead and take USABO as well. Worst thing that can happen is you don't move on.</p>
<p>thanks for your input, cadaeibfed. I'm just a freshman, but i'm thinking of taking AP Bio next year. I'll definitely consider USABO.</p>