A Conflict of Interest is defined as a set of conditions in which professional judgment concerning a primary interest, such as the validity of research, may be influenced by a secondary interest, such as financial gain.
A Declaration of Interest (sometimes called a Disclosure Statement) is a notification from the author that there's no financial/personal interest or belief that could affect their objectivity, or if there is, stating the source and nature of that potential conflict.
To prevent ambiguity, authors must state explicitly whether potential conflicts do or don't exist, so you may be asked to provide one, even if no conflicts exist.
See the Conflict of Interest Factsheet for more information.
For a generic template Declaration of Interest/Author Agreement form click here.