The Empirical Correlation Coefficient (CORR) is an evaluation metric in time series forecasting,1

$$\mathrm{CORR} = \frac{1}{N} \sum_{i=1}^N \frac{ \sum_t (y^{(i)}_t - \bar y^{(i)} ) ( \hat y^{(i)}_t -\bar{ \hat y}^{(i)} ) }{ \sqrt{ \sum_t (y^{(i)}_t - \bar y^{(i)} )^2 ( \hat y^{(i)}_t -\bar{\hat y}^{(i)} )^2 } }$$

where $y^{(i)}$ is the $i$th time series, ${} _ t$ denotes the time step $t$, and $\bar y^{(i)}$ is the mean of the $i$th forecasted series, i.e., $\bar y^{(i)} = \operatorname{mean}( y^{(i)} _ { t \in \{T _ f, T _ {f+1}, \cdots T _ {f+H}\} } )$.

Planted: by ;

Lei Ma (2022). 'Empirical Correlation Coefficient (CORR)', Datumorphism, 08 April. Available at: https://datumorphism.leima.is/cards/time-series/ts-corr/.