A deposition or actual trial testimony consists of two parts: the direct examination and the cross-examination. Direct examination precedes the cross-examination and involves testimony brought forth by the retaining attorney. Cross-examination occurs immediately after the direct examination and is carried out by the opposing attorney. The main purpose of cross-examination is to test the “reliability, accuracy and credibility” of witnesses’ testimony produced during the direct examination. Questions posed during cross-examination typically fall into two categories: those intended to expose weaknesses or errors in the expert witnesses’ data acquisition or interpretations, and those related to expose biases in the testimony. During cross-examination, expert witnesses are expected to give responsive answers. That is, they are to provide relevant answers, but the answers need not be those implicitly desired by the opposing attorney. The opposing attorney may use several tactics during cross examination including: challenging credibility, establishing doubt, leading questions, feigned ignorance, the cut-off (e.g., testimony of witness terminated to stop the witness from providing further information that could be detrimental to the opposing attorney’s position), intentional ambiguity, implying impropriety, rattling the witness, and many others.