Cross-examination: The expert witness may be called upon to retrace his steps, explain and justify his position, and harmonize his views in the case with prior writings, depositions or trial testimony from other matters/cases.
Cross-examination is one of the most misunderstood aspects within the adversarial system. It need not be a fearful experience for the expert. Cross-examination is designed to guarantee a fair trial. With regard to experts, cross-examination has six general purposes. These are to establish the expert's:
- Lack of perceptive capacity or application (i.e., failure to do one's homework).
- Inadequate recollection of the applicable facts.
- Bias, prejudice or interest in the outcome (or motivation to give a particular testimony).
- Questionable character, reputation or qualifications.
- Prior inconsistent statements or conduct (i.e., if the expert testified to different conclusions in another case in which the facts and evidence were approximately the same, that can be used to impeach their testimony).
- Inconsistency with recognized published authorities, so-called learned treatises.
Cross-examination can present an opportunity to solidify and drive home the expert's conclusions and opinions previously stated during direct examination. Witnesses should be honest and should rely on their technical expertise and the scientific method, on which their testimony is based. They should provide credible and effective expert testimony and should be able to use cross-examination in a positive way. (See Trial for further information.)
Additional Online Courses
- What Every First Responding Officer Should Know About DNA Evidence
- Collecting DNA Evidence at Property Crime Scenes
- DNA – A Prosecutor’s Practice Notebook
- Crime Scene and DNA Basics
- Laboratory Safety Programs
- DNA Amplification
- Population Genetics and Statistics
- Non-STR DNA Markers: SNPs, Y-STRs, LCN and mtDNA
- Firearms Examiner Training
- Forensic DNA Education for Law Enforcement Decisionmakers
- What Every Investigator and Evidence Technician Should Know About DNA Evidence
- Principles of Forensic DNA for Officers of the Court
- Law 101: Legal Guide for the Forensic Expert
- Laboratory Orientation and Testing of Body Fluids and Tissues
- DNA Extraction and Quantitation
- STR Data Analysis and Interpretation
- Communication Skills, Report Writing, and Courtroom Testimony
- Español for Law Enforcement
- Amplified DNA Product Separation for Forensic Analysts