This report examines duty tasks performed by military occupational specialty 31M, Multichannel Communications Equipment Operator, whose members operate communications systems providing division- and corps-level command and control. The intent was to develop quantitative analyses based on objective measurement of soldier and unit performance aimed at improving the Army's ability to set appropriate performance standards and to develop quantitative estimates of the link between personnel aptitude and Army operational performance. The study finds that the Armed Forces Qualification Test (AFQT) score has a direct, consistent effect on the ability of communications personnel to provide effective battlefield communications to Army units. The evidence suggests that AFQT scores have a sizable effect on group performance. Groups that are on average "smarter" outperform other groups. The study concludes that a lowering of accession standards will substantially reduce the probability of operator success in operating and troubleshooting communications systems.