Red marker = optimal effort $e^*$. Dashed vertical line shows the maximum.
$e^*$ as a function of team size $N$
Marginal contribution $\partial\mathbb{P}/\partial e_i$ vs $N$
$e^*$ as a function of bonus $b$
$e^*$ as a function of effort cost $k$
$e^*$ rises with $N$ and $b$, falls with $k$. The marginal contribution curve
$\partial\mathbb{P}(R=1)/\partial e_i = p\,\gamma\,N^{\gamma-1} e^{*\gamma}/N$
always decreases with $N$ — formalising team moral hazard.
Sensitivity of $e^*$ to ±50% parameter change (tornado chart)