The Board of Immigration appeals issued a precedential decision on December 17, 2020, Matter of M-A-M-Z-, 28 I&N Dec. 173. This decision relates to the testimony of expert witnesses in immigration court proceedings. The Board found that expert witnesses provide evidence, but that the immigration judge must determine whether to accept that evidence as factual findings. The Board also clarified that if an immigration judge does not make factual findings consistent with the evidence from a credible expert witness, the judge should explain the reasons for not doing so.
Read the full decision in Matter of M-A-M-Z-, 28 I&N Dec. 173, at the BIA website.