From Halopedia, the Halo wiki
Doctor O. Cheng was a professional that was also a member of the UEG Strategic Forecasting and Scenario Planning Group at the close of the Human-Covenant War. On October 9, 2552, Cheng forwarded Log 01-0921, an intelligence report incorporating recent naval losses during the Fall of Reach, to the UNSC Security Council. The accepted scenario concluded that human civilization would likely fall to the Covenant with currently available military assets and remaining industrial bases. Additional classified appendices and opinions from the Office of Naval Intelligence and the UNSC Special Topics Committee were attached to the report, but redacted. Cheng made sure to communicate that Fleet Admiral Joseph Harper disagreed with the conclusions of the group.