  For Verizon MediaDemand Side Platform(DSP), forecasting of ad campaign
performance not only feeds key information to the optimization server to allow
the system to operate on a high-performance mode, but also produces actionable
insights to the advertisers. In this paper, the forecasting problem for CPA
lines in the middle of the flight is investigated by taking the bidding
mechanism into account. The proposed methodology generates relationships
between various key performance metrics and optimization signals. It can also
be used to estimate the sensitivity of ad campaign performance metrics to the
adjustments of optimization signal, which is important to the design of a
campaign management system. The relationship between advertiser spends and
effective Cost Per Action(eCPA) is also characterized, which serves as a
guidance for mid-flight line adjustment to the advertisers. Several practical
issues in implementation, such as downsampling of the dataset, are also
discussed in the paper. At last, the forecasting results are validated against
actual deliveries and demonstrates promising accuracy.
