A secondary driver is a system component that is hypothesized to activate each primary driver. It is the "how" of change.
In NILS, secondary drivers are listed below primary drivers. Access them either through the driver diagram, or through the Drivers button to the left of the Diagram button. To view text about secondary drivers, select the ‘i’ icon.
Secondary drivers are listed out beneath primary drivers, as seen below. In this case, 1.1, 1.2...are secondary drivers.