The article presents an analysis of melody annotation disagreements in a novel dataset containing annotations of a selection of Haydn and Mozart string quartet movements. For this purpose the following definition of melody from the music information retrieval (MIR) community is applied: the sequence of monophonic pitches that a listener might sing or hum when asked to reproduce a polyphonic piece of music, and encompasses the core identity of the piece. The resulting collection of annotations makes up the new Melody Annotated String Quartets (MASQ) dataset, available online. The rates and types of disagreements between annotators are discussed, as well as the influence of musical form and style on melody perception and the suitability of the given definition of melody
