The start-finish relationship is very seldom used and has even been dropped from some of the project management scheduling software packages. This relationship is stated in the same sentence as the finish-start relationship except that the words start and finish are substituted for finish and start. The relationship is stated like this: The independent activity in the relationship must start before the dependent activity can finish. This says that where there are two activities connected by an arrow, the one that is connected to the tail of the arrow must start before the activity connected to the head of the arrow is allowed to finish. It does not say that the dependent activity must finish then. The dependent activity could finish later than that time, but it is not allowed to finish any sooner than the start of the independent activity. For an example, let’s use the wedding cake and the supervisor again. The project is still to construct a wedding cake. The task in this example is to apply the frosting to the cake. We do not want to finish applying the frosting to the cake until the master chef is on the scene. The two tasks then are:
(1) apply frosting to cake and (2) master chef supervises cake construction.
The start-start relationship says that I cannot start putting the frosting on the cake until I have the master chef present. The start-finish relationship says that I can start putting on the frosting of the cake before the master chef is present, but I am not allowed to finish putting on the frosting until the master chef has started supervising. Notice that I could, logically, start putting the frosting on any time before the master chef begins to supervise. The relationship constricts the finish of the activity of frosting the cake to be no sooner than the beginning of the master chef supervising the cake construction. These relationships must be available to project managers and schedulers in order to be able to schedule all of the real relationships that are necessary to properly schedule a project. They are seldom used until attempts are made to reduce total schedule time. In the examples involving frosting the cake, I related the frosting of the cake to the presence of the master chef to supervise the operations.
At first the relationship was a start-start relationship, in which the frosting operation had to wait until the master chef began supervising. If we were trying to shorten the schedule, one of the things that might help would be to change the relationship between these to activities to a start-finish relationship. This would allow the frosting of the cake to begin much sooner but still require that the master chef supervise the completion of the task.
(1) apply frosting to cake and (2) master chef supervises cake construction.
The start-start relationship says that I cannot start putting the frosting on the cake until I have the master chef present. The start-finish relationship says that I can start putting on the frosting of the cake before the master chef is present, but I am not allowed to finish putting on the frosting until the master chef has started supervising. Notice that I could, logically, start putting the frosting on any time before the master chef begins to supervise. The relationship constricts the finish of the activity of frosting the cake to be no sooner than the beginning of the master chef supervising the cake construction. These relationships must be available to project managers and schedulers in order to be able to schedule all of the real relationships that are necessary to properly schedule a project. They are seldom used until attempts are made to reduce total schedule time. In the examples involving frosting the cake, I related the frosting of the cake to the presence of the master chef to supervise the operations.
At first the relationship was a start-start relationship, in which the frosting operation had to wait until the master chef began supervising. If we were trying to shorten the schedule, one of the things that might help would be to change the relationship between these to activities to a start-finish relationship. This would allow the frosting of the cake to begin much sooner but still require that the master chef supervise the completion of the task.