PPI Repository

Formal Definition

$\frac{\mathit{SUC}\mathit{^{\times}}(a)}{\mathit{U}\mathit{^{\times}}(a)}$
The $\mathit{\times}$ indicates that the PPI can take multiple forms, in this case, $\mathit{\times} \in \{\mathit{sgl}, \mathit{sum}\}$. If $\mathit{\times} = \mathit{sgl}$, then the function considers single events of activity instances for outcome unit calculations, i.e., it uses $\mathit{SUC}\mathit{^{sgl}}$ and $\mathit{U}\mathit{^{sgl}}$; if $\mathit{\times} = \mathit{sum}$, then the function considers the sum of all events of activity instances for outcome unit calculations, i.e., it uses $\mathit{SUC}\mathit{^{sum}}$ and $\mathit{U}\mathit{^{sum}}$.