What type of expert opinion is typically not allowed in Ohio?

In Ohio, expert opinion that is based on hearsay evidence is typically not allowed because hearsay, by definition, refers to statements made outside of the court that are being used to prove the truth of the matter asserted. This type of evidence is generally inadmissible in court due to concerns over its reliability and the inability to cross-examine the original source of the statement.

Expert opinions must be grounded in reliable and relevant data, which is why the other types of expert opinion mentioned are generally permissible. Opinions based on personal observation are often valid because they reflect the expert's firsthand knowledge. Likewise, opinions grounded in specific factual data admitted at trial and those based on empirical research are acceptable, as these are credible sources that can withstand scrutiny and allow for cross-examination. Therefore, the restriction of hearsay evidence in expert opinions ensures that the testimony provided is based on substantiated and reliable information, upholding the integrity of the judicial process.