 Heartbeat counting score

A common score compares reported counts $C_j$ with recorded counts $N_j>0$ over $m$ intervals: $A=m^{-1}{\sum }_{j=1}^m(1-|N_j-C_j|/N_j)$. The absolute error is normalized by the recorded count. Equal reports give $A=1$, but the score does not identify the reporting strategy. The unclipped expression is at most one and can be negative for sufficiently large overcounts.