What is Forwards and Backwards Scanning?
In HSC Standard Math, we use forwards and backwards scanning to determine the earliest start time and latest start time for a project.
For a project, we always want it to be completed in the shortest time possible. In order to predict, we need to find out the Earliest Starting Time (EST), which indicates that a project cannot start until whatever unit of time is given after the start of the project. The process is called Forward Scanning.
Sometimes, we have some flexibility in the start time, so long as they occur before the Latest Start Time (LST) to ensure the project is still completed in the shortest time possible. LST is calculated in reverse starting at the final activity working backwards. This process is called backward scanning.
The following video demonstrates how forward and backward scanning works in critical path analysis in order to determine the earliest start time and latest start time.