If an eyewitness is not available, identity may be proved by circumstantial evidence. The historic presumptions that a child under age six is not competent to testify, and that a child of fourteen years is a competent witness, have been abandoned by the Illinois courts. All persons, regardless of age, are now presumed to be competent. A person is disqualified only if incapable of expressing himself or herself, or if incapable of understanding the duty to tell the truth. A party objecting to the competency of a witness must raise the issue by motion and assume the burden of proof.
Civil law follows the same general competency rules and foundation requirements as criminal law.
Although the burden to prove incompetency is on the opponent of the witness, the proponent generally lays the foundation with a child witness to pre-empt the challenge and add weight to the testimony. The person who prepared the record is not a necessary witness to establish the foundation. Any person familiar with the record preparation procedure may establish the foundation. The record is necessary to the regular conduct of the business. The record was prepared at or near the time of the events recorded in the document.