Comparison definition. (1) A declaration against interest is a statement by a third party. An admission is by a party to the litigation. (2) The declarant against interest must be unavailable. There is no such requirement for admissions. (3) A declaration against interest must be based on personal knowledge. An admission can even be based on totem pole hearsay. (4) A declaration against interest must be against interests when made. An admission is only inconsistent with a present position.