In CPM scheduling, every task has a relationship with every other task. One way to identify a task’s relationship with another is with the “Start/Finish” label. There are four variations of this relationship, and they go as follows:
Finish to Start – In this case, the next task cannot begin until the first task is finished. For example, if two tasks are “buy turkey & other ingredients” and “make a turkey dinner,” you can’t start making the turkey dinner until you’ve bought the ingredients for it.
Finish to Finish – Here, you cannot complete the next task until the first task is also done. For example, you can’t stock a retail shelf completely until you have all of the products. But you can begin to stock with the products that you already have.
Start to Start – In this case, in order to begin the next task, you must have already begun the previous task. Take the stocking example again. You can’t begin to stock a shelf until you have some products to put on the shelf. So, they must transport some products before stocking begins.
Start to Finish – Here, you can’t finish the next task until the preceding task begins. Take these two tasks for a chef: making the meal and taste testing it. The chef must start to make the meal before he can test the taste, but the meal does not need to be completed before he tests it.