  Chord estimation metrics treat chord labels as independent of one another.
This fails to represent the pitch relationships between the chords in a
meaningful way, resulting in evaluations that must make compromises with
complex chord vocabularies and that often require time-consuming qualitative
analyses to determine details about how a chord estimation algorithm performs.
This paper presents an accuracy metric for chord estimation that compares the
pitch content of the estimated chords against the ground truth that captures
both the correct notes that are estimated and additional notes that are
inserted into the estimate. This is not a stand-alone evaluation protocol but
rather a metric that can be integrated as a weighting into existing evaluation
approaches.
