In a military, scouts were units who were sent ahead of the lager group to gather intelligence. In interstellar expansion, scouting was accomplished via scout ships.
During the initial expansion of the Dalek Empire, reconnaissance scouts were sent ahead of the Dalek Fleet, gathering information on alien planets before summoning the fleet. (TV: Resolution) During the Imperial-Renegade Dalek Civil War, the Imperial Daleks made use of Scout Daleks. (PROSE: Remembrance of the Daleks) Scout Daleks made use of Dalek scout ships for their missions. (PROSE: Dalek Combat Training Manual) During the Kotturuh crisis, the Dalek Time Squad deployed scout ships in the Battle of Mordeela and later used them to collect subjects for the Symbiont and hunt down the remaining Kotturuh. (PROSE: All Flesh is Grass)
A book about the history of N-Space speculated that, among other theories, the Dalek War Machine in the Morok Space Museum had been a solitary scout Dalek that had been overpowered by the Morok Empire. (PROSE: The Whoniverse) By contrast, The Time Lords believed that the Dalek had been one of the combatants of the Thal-Dalek battle, its inert shell claimed by Morok scouts who had visited Skaro sometime prior to the 2150s Dalek invasion of Earth. (PROSE: Dalek Combat Training Manual)
The Cybermen made use of Cyber-Scouts. (TV: The Five Doctors) When a cosmic cloud appeared over Mondas, a Cyber-Scout was sent through, unaware that it was caught in a bootstrap paradox. (COMIC: The Prodigal Returns) Following Mondas being thrown out of its orbit, scout ships were sent out to find Earth. One of these vessels found the planet but was caught in a time storm before it could report. The two unit vessel broke apart Kreel falling to Edinburgh in the late 19th century, (AUDIO: Way of the Burryman) while his partner landed in 1925 Berlin. (AUDIO: Monsters in Metropolis) Two other CyberMondan scouts, Bremm and Gramm also found Earth but crashed in the mountains of Austria in 19th century. (AUDIO: The Silver Turk)