Evidence
Relevance and Its Limits
Relevance is the threshold: evidence must tend to prove or disprove a fact of consequence. Even relevant evidence may be excluded under Cal. Evid. Code § 352 (substantially outweighed by prejudice, confusion, or undue consumption of time). Character evidence is generally inadmissible in civil cases and in the prosecution's case-in-chief in criminal cases, with exceptions (e.g., defendant's character for peacefulness, victim's character).
Hearsay
Hearsay is an out-of-court statement offered for its truth. Non-hearsay uses: impeachment, effect on listener, verbal acts, state of mind. Exceptions: present sense impression, excited utterance, then-existing mental state, statements for medical diagnosis, recorded recollection, business records, public records, ancient documents, former testimony. California has its own Evidence Code numbering - a common trap.
Witnesses and Privileges
Impeachment by prior inconsistent statement, bias, conviction, reputation for truthfulness. Privileges: attorney-client, physician-patient, spousal (confidential marital communications and testimonial privilege), clergy, psychotherapist. California recognizes a broader set of privileges than federal law.
Traps
Offering hearsay for a non-truth purpose without identifying the purpose; confusing California and FRE exceptions; forgetting that a prior inconsistent statement under oath is substantive evidence but unsworn is only impeachment.
Rule of Thumb
Before admitting any statement, ask: (1) Is it offered for its truth? (2) If yes, does an exception apply? (3) Even if admissible, does § 352 or a privilege bar it?