What is the test for credibility of an allegation of sexual assault?

Having questioned Singh's credibility, the agency reasonably relied further on his failure to rehabilitate his claim with corroborating evidence. "An applicant's failure to corroborate his or her testimony may bear on credibility, because the absence of corroboration in general makes an applicant unable to rehabilitate testimony that has already been called into question." Biao Yang v. Gonzales, 496 F.3d 268, 273 (2d Cir. 2007). Indeed, Singh's wife's affidavit was inconsistent regarding the date of his first arrest, his political party's letter did not corroborate his arrests, and his medical evidence did not corroborate his hospitalization.