In terms of chords and melody, Do They Know It's Christmas is more basic than the typical song, having below average scores in Chord Complexity, Melodic Complexity, Chord-Melody Tension, Chord Progression Novelty and Chord-Bass Melody.
Do They Know It's Christmas is written in the key of C Major. According to the Theorytab database, it is the most common key in all of popular music. See the C Major Cheat Sheet for popular chords, chord progressions, downloadable midi files and more!