Personal Knowledge

Every witness (except an expert witness or a witness testifying to admissible hearsay) must testify from first-hand knowledge.

Leading and Argumentative Questions

Leading questions are those in which the examiner suggests in the question the answer which he desires. 

Leading questions are not permitted on direct examination until a witness's memory is exhausted, but are permissible on cross-examination.

An argumentative question (e.g., one that starts "Don't you know that  ") is inadmissible even on cross-examination.

Refreshing Recollection

Present memory refreshed occurs when the witness's memory is revived (e.g., by reference to a document).  The witness then testifies to what he remembers.  The rules regarding hearsay and admissibility of writings are inapplicable.

On the other hand, past recollection recorded occurs when a witness has made a written record on a matter while his memory was fresh, and his memory of that matter is exhausted and cannot be revived.  The document itself, which comes within a hearsay exception, is read to the jury and must satisfy the requirements for admissibility of a writing.

If a witness brings written documents with him while testifying, opposing counsel can examine them as a matter of right in the course of cross-examination.

Objections and Offers of Proof

An objection must be made as soon as opposing counsel knows she has grounds to object.

The objection must delineate the specific ground for objection unless the specific ground is obvious from the context.

A party can waive grounds for objecting by introducing similar inadmissible evidence himself.

Hearsay evidence which would be inadmissible at trial is admissible before a judge hearing evidence on a preliminary question of fact.

An offer of proof is required only when an objection to a question is sustained.  The party must state for the record but out of the hearing of the jury what the answer to the question would be, if known.

To preserve an issue for appeal, counsel must object to the admissibility of evidence at the time it is offered, but need not renew the objection at closing if the court has given a definitive ruling.

Lay Opinions and Expert Witnesses

A layperson can testify in the form of opinion with respect to matters on which laypersons are competent to form opinions, if the opinion is based upon personal knowledge or perception and is helpful to a clear understanding of a fact in issue.

A lay witness cannot testify on matters on which only experts are qualified to give opinions, i.e., opinions based on scientific, technical or other specialized knowledge.

It is within the discretion of the trial court whether an expert is qualified to give testimony that will assist the trier of fact.  An expert witness need not testify from personal knowledge, but instead may draw inferences from facts presented to him and may rely on the opinions of other experts if to do so is customary in the field of expertise.  So long as reasonably relied on by experts in the field, the facts or data forming the basis of the expert’s opinion need not be independently admissible in evidence, but the testimony must be based on “sufficient” facts or data.

The court plays a “gatekeeper” function in determining whether the expert’s testimony is the product of reliable principles and methods and the expert has applied these principles and methods reliably to the facts of the case.

An expert witness can be cross-examined about specific instances in his background which bear on his qualification as an expert and may be required to disclose on cross-examination the facts or data underlying his opinion. 

Except for the mental state of a criminal defendant, an expert witness can give an opinion on the ultimate issue in a case.

Qualifications and Competence of Witnesses

Every person is competent to be a witness except:

1. a witness who would be incompetent under state law if state law controls;
2. a witness who lacks personal knowledge, except for an expert witness;
3. a witness who cannot understand that he must tell the truth;
4. the trial judge;
5. a juror.

The Federal Rules of Evidence require that a federal court apply the state's rule on matters of competency of witnesses and privilege if state law provides the basis for decision in the federal court (as it would in diversity cases).

Judicial Notice

A court must upon request, or may of its own motion take judicial notice of any fact which is either generally known within the territorial jurisdiction, or is capable of ready and accurate determination by sources whose accuracy cannot be questioned. 

A court will judicially notice the law of a state in which it is sitting, and of federal law.  The law of sister states and foreign countries will be noticed if there is statutory authorization.

A jury in a criminal case is not bound to take as true matters which have been judicially noticed.

Cross-Examination

If the opposing party is deprived of his opportunity to cross-examine a witness, the remedy is to strike the direct examination.

If part of a document is admitted in evidence by one party, the opposing party has the right to introduce any other part of the same document which ought in fairness be considered with the part already in evidence, even if such evidence would otherwise be inadmissible.

An out-of-court declarant whose statement is admissible hearsay may be impeached in the same manner as an in-court witness.

Prior Inconsistent Statements

A prior inconsistent statement is admissible only to impeach unless it comes within an exception to the hearsay rule or it was given under oath, in which case it is admissible to prove the matter asserted.

Extrinsic evidence of a prior inconsistent statement is inadmissible to impeach credibility unless the attention of the witness is called to the statement.

Bias

Unless the witness admits the fact relating to bias on cross-examination, extrinsic evidence can be introduced to prove bias.

If offered to prove bias, usually inadmissible evidence (such as insurance coverage and other criminal convictions) is admissible.

Religious beliefs of the witness cannot be used to impeach credibility.

Impeachment - Convictions

Prior convictions of a person can only be introduced to impeach credibility after that person has testified.

Evidence of convictions for juvenile crimes and for misdemeanors not involving dishonesty or false statement is always inadmissible to impeach credibility.

The party proffering a witness can anticipate impeachment of the witness through the use of prior convictions by introducing the convictions against the witness on direct examination.

The court must admit any conviction involving dishonesty or false statement against any witness, as long as the conviction is recent (i.e., less than 10 years old).

The court may admit a recent conviction of the criminal defendant for a crime punishable by death or at least one year imprisonment only if the impeaching party first shows that the probative value of the conviction outweighs its prejudicial effect.  The court must admit a recent conviction of a witness (other than the accused) for a non-fraud crime punishable by death or at least one year imprisonment unless the objecting party shows that the prejudicial effect of the impeachment substantially outweighs the probative value of the evidence.

A conviction more than 10 years old can only be admitted against any witness only if the impeaching party first shows that the probative value of the conviction substantially outweighs its prejudicial effect.

Impeachment - Prior Bad Acts

Evidence of bad acts which show fraudulent conduct can be inquired into on cross-examination to impeach credibility, but extrinsic evidence of such conduct cannot be introduced.

Impeachment - Reputation for Veracity

The witness’s truthfulness can be attacked either by opinion evidence or by reputation evidence.

The character of a witness for truthfulness cannot be introduced until that character trait has been attacked.

Impeachment by Contradiction

Extrinsic evidence cannot be used to contradict a witness on a collateral matter.

Rehabilitation and Redirect Examination

Testimony on redirect examination must relate to those matters asked on cross-examination.

A witness's credibility can be rehabilitated only with respect to the manner in which it has been attacked.  For example, evidence of good character can only be presented if the witness's character has been attacked.

Presumptions

There are various types of presumptions with varying effects; some are rebuttable and others are irrebuttable.  If the party seeking the benefit of a rebuttable presumption introduces evidence from which the jury can find the basic fact giving rise to the presumption, the party against whom the presumption operates must introduce evidence contradicting the presumed fact or face a directed verdict against him on that fact.  Most presumptions do not change the burden of persuasion but only the burden of going forward.