n. A large number of workers hired to help complete a big or complex project, particularly one that is running behind schedule.
2006
The business sponsor of the project wanted the system to be able to support dental when the system went live. "We looked at it and said there was no way," he recalls. "We held to our guns. We knew if we bent and said yes, we really were not going to be successful. You couldn't use the Mongolian horde theory—bring in more people—because we were dealing with all the same modules."
1997
Everbody in software knows the "Mongolian hordes" technique. It implies throwing people at the problem to cut a few months off the development schedule.
1996 (earliest)
Mongolian Hordes technique n. Development by gang bang. lmplies that large numbers of inexperienced programmers are being put on a job better performed by a few skilled ones. Also called Chinese Anny technique.