Models are evaluated on the original SQuAD dev set and 4 adversarial datasets: <cite>AddSent</cite>, the adversarial evaluation set by <cite>Jia and Liang (2017)</cite> , and 3 variations of <cite>AddSent</cite>: AddSentPrepend, where the distractor is prepended to the context, AddSentRandom, where the distractor is randomly inserted into the context, 4 and AddSentMod <cite>(Jia and Liang, 2017)</cite> , where a different set of fake answers is used and the distractor is prepended to the context.