Alpha Ramp [better] -

For a portfolio of $N$ similar event stocks, the average alpha ramp is: $$\overline\alpha t = \frac1N\sum i=1^N \alpha_i,t$$

The from time $T_1$ to $T_2$: $$\textAlphaRamp(T_1, T_2) = \sum_t=T_1^T_2 \alpha_i,t$$ alpha ramp

Then the daily alpha is: $$\alpha_i,t = R_i,t - E[R_i,t]$$ For a portfolio of $N$ similar event stocks,