A witness testifying in the form of an opinion may state on direct examination the reasons for his opinion and the matter (including, in the case of an expert, his special knowledge, skill, experience, training, and education) upon which it is based, unless he is precluded by law from using such reasons or matter as a basis for his opinion. The court in its discretion may require that a witness before testifying in the form of an opinion be first examined concerning the matter upon which his opinion is based.
Cal. Evid. Code § 802
Expert and Other Opinion Testimony Generally
Applied in 23 court decisions — leading case 54 Cal. 3d 612 - People v. Mickey (1991)
Most recently applied in 10 Cal. 5th 786 - People v. Turner (November 2020)
Enacted by Stats. 1965, Ch. 299.
How often courts cite this section
Court decisions citing this, by year. The dip in the last several years is a data-coverage gap, not a real trend — our corpus holds fewer opinions from the most recent years, so recent citations are undercounted.
Official source: California Legislative Information. Reproduced from public-domain California statutes; confirm against the official source for the current text. Not legal advice.