Identifying Dependencies

00:02 Things are chugging along nicely at this point.

00:04 We have a work breakdown structure and activity list.

00:08 We've got an estimation of their durations and we stuck some buffers on to cover our backs. Wow.

00:13 Way to go. But things do look a bit like an activity soup right now.

00:19 We need to jumble this mess and see how activities link with each other.

00:24 In other words, we need to understand their dependencies.

00:28 It's not hard to imagine how some tasks are dependent on others.

00:33 You can't have the cars delivered without a showroom, and you can't build your showroom until you've started digging.

00:39 And you can't start digging until you have the machinery on site.

00:43 You can, however, start recruiting the sales team.

00:47 So let's look at the four main reasons why dependencies exist between tasks. First logical dependency. This is just like what I described.

01:01 You can't put windows in your showroom until you've built walls.

01:06 Second, we've got resource constraints.

01:09 Lack of resources can affect the sequencing of tasks.

01:13 Let's say you have to work packages as part of your showroom project.

01:17 One for performing a financial comparison between two potential interior designers and another for preparing a detailed report on travel expenses.

01:26 But you only have one business analyst and nobody else qualified to perform the tasks. The two tasks cannot be completed simultaneously.

01:35 Therefore, your business analyst has to finish one before they can start the other.

01:42 Third, we have external dependencies.

01:45 These can be anything from building work that needs to be signed off by the city to paint work that can only be done in good weather.

01:53 You get it. The activities that are affected by external sources.

01:59 The fourth are called soft dependencies.

02:02 These are applied by the project manager themselves and could include things like a task not going forward unless the project manager has checked the previous task.

02:11 They are called soft dependencies as they are easily amendable due to the fact that the project manager set them in the first place.

02:19 Now let's have a look at the types of dependencies.

02:23 For again, is the magic number here.

02:29 First we have finish to start, where the second task cannot start until the first has finished.

02:37 The task paint.

02:39 The whole room cannot start until you finish the task by paint.

02:45 Second there is finish to finish where the second task cannot be finished until the first has been finished.

02:52 The task, paint the whole room cannot be finished before task paint the fourth wall is fully finished.

03:00 Third is start to start where the second task can only start when the first starts the task paint.

03:07 The whole room must start.

03:09 So the task paint, the first wall can also start.

03:14 And lastly the not as common.

03:16 Start to finish where the second task has to start before the first can finish.

03:23 Let's step away from the painting.

03:25 Examples for this one and imagine the construction site needs 24 hour security. Guard two's shift must start before Guard one's shift can finish.

03:36 This way there will be no interruption in the surveillance for any thieves to sneak in.

03:43 As always, the project manager must take all these factors into consideration because any missed dependencies are sure to cause delays and increase costs.

03:52 Once the project manager has worked out the dependencies, we can apply the critical path method. We came across a couple of lessons ago to potentially find out the shortest time in which we can complete the project.

04:04 So let's look at this next.