Building SCV Harassment

Building SCV harassment is a situation that occurs regularly in the early stages of the game, when a scouting worker attacks the SCVs that are building Barracks, Supply Depots or Command Centers of a Terran player.

Because the Terran player has no units other than SCVs, the Terran player will have to pull one or more SCVs from the mineral line to defend or risk losing SCVs and being delayed.

Because at the early stages of the game an SCV can mine 0.75 m/s, using an SCV to defend for the whole time necessary to buld a Barracks (65 seconds) corresponds to 48.75 minerals not mined. In practice however, the time the SCV is threatened is far less.

Swapping a hurt building SCV with a fresh one costs twice the time to transfer the worker, which in practice corresponds to something between 10 to 20 seconds depending on the map.

This situation is one of the few where the "select builder" command can be useful.