Understanding Project and Task Dependencies

Understanding Project and Task DependenciesUnderstanding Project and Task DependenciesProject Managers reference project dependencies as the relationships between individual tasks in a projectdiagram. Preceding tasks must be completed before moving on to the next or succeeding tasks. All of the tasks required to achieve the projects scope are sequenced according to their dependencies for each other, and then resources are linked to the tasks and a project schedule constructed. The project or task dependencies are critical for the following Sequencing the work packages (tasks) in a project plan.Calculating the critical path (longest path/duration) of tasks in a project plan.Identifying resource and scheduling issues and making supporting decisions.Monitoring and managing as part of the overall project plan.Identifying opportunities to accelerate the schedule via fast-tracking or crashing. Examples of Project Task Dependencies While the analysis of task dependencies for a large pro ject is a complex task often requiring computer software, consider a few simple examples to illustrate the concept. Example 1 Making Coffee Imagine getting out of bed in the morning, yawning, and making your way to the kitchen to discover that you forgot to preset your coffeemaker to brew automatically. It is now up to you to shake off the sleep and start the coffee brewing. You know that you need to complete the following tasks Add waterGrind the coffee beansMeasure the coffee into the filterAdd a coffee filterPlace the carafe on the heating trayPress brew Of course, there is a proper order to this process. You would not press brew before completing all of the other steps. A proper sequence of events taking into account dependencies might be as follows Grind the coffee beansAdd a coffee filterMeasure the coffee into the filterAdd waterPlace the carafe on the heating trayPress brew. In this sequence of tasks, you could not measure the coffee into the filter before you ground the bea ns. Grinding the coffee beans is a predecessor activity for measuring the coffee into the filter. The measuring step is a succeeding activity. All of the tasks are predecessor activities to the step Press brew. Example 2 Installing a Lawn Sprinkling System in a Brand New House Important tasks for this include Install the sod (lawn).Dig the trenches for and install the sprinkling system hoses.Locate the sprinkler heads.Grade the lot.Fill the trenches. The proper sequence of events taking into account task dependencies is as follows Grade the lot.Locate the sprinkler heads.Dig the trenches for and install the sprinkling system hoses.Fill the trenchesInstall the lawn. Understanding the dependencies in this example allows the landscaper to plan for grading and digging equipment, ensuring the availability of supplies and scheduling the proper resource for each step. Types of Project Planning Dependencies There are four types ofproject planningdependencies. They establish relationship s among the tasks. Below, they are listed in the order most often used Finish-to-start (FS) The first task must complete before the second task can start. For example, the task Write code module 1 must finish before the task test code module 1 can begin.Finish-to-finish (FF) The second task cannot finish before the first task finished. The task all code tested cannot finish before the task test code module x finishes.Start-to-start (SS) The second task doesnt start until the first task starts. The task write training manual must start before the task write chapter 1 of the training manual can start. Start-to-finish (SF) The first task must start before the second task can finish. The task assign coder for module 3 must start before the task all work assigned can finish. Categories of Project Planning Dependencies There are also dependencies with other projects. Planning dependencies fall into three categories logical, resource-based, or preference. Below are three types of proje ct planning dependencies Logical planning dependencies ansicht are dependencies that are logic-driven. You cant paint a wall before its built. You cant test a code module until after its written.Resource-based planning dependenciesThese are dependencies where the task could be accomplished faster or sooner if you had more resources. The manual could be written faster if you had more than one writer. You could write more code except all the other developers are committed to other projects.Preference planning dependenciesThese are tasks that could be scheduled differently, but the project manager chooses to schedule this particular order. The Bottom Line Project managers must be able to plan for and manage the dependencies among tasks in their projects. Dependencies impact scheduling and resource activities, and it is critical to understand these relationships when looking for opportunities to improve the project schedule. Updated by Art Petty