Who has the greater IMA a screw with closely spaced threads or a screw with threads spaced farther apart?

Holding the diameter of the screw constant, closely spaced threads (fine pitch) have a higher mechanical advantage than thread which are spaced farther apart (course pitch). Mechanical advantage is the ratio of travel of the applied force to the ratio of the imparted force. Because the screw must rotate more times to insert a given depth, fine pitch has a higher mechanical advantage.