(A) A person is qualified to testify as an expert if he has special knowledge, skill, experience, training or education sufficient to qualify him as an expert on the subject to which his testimony relates. Against the objection of a party, such special knowledge, skill, experience, training or education must be shown before the witness may testify as an expert.(B) An expert witness’ special knowledge, skill, experience, training or education may be shown by any admissible evidence, including his own testimony.
Puerto Rico Legal Code