What are dependencies in project management?

A dependency is one of those words that crop up regularly in everyday work: in Gantt charts, for example, or in a business plan or schedule. But what does it actually mean? In real life, what are dependencies in project management for? What do they do?

In this article, we’ll answer these questions and more, including top tips for tools such as Wrike to help us manage dependencies effectively.

What is a dependency in project management?

A dependency in project management refers to a series of tasks that are interrelated, i.e., one relies on the other in some way. When it comes to tasks, there are several different types of dependencies in project management:

Finish to start: Task B cannot start until task A has been completed
Start to start: Task B cannot start until task A starts
Finish to finish: Task A cannot be completed until task B is completed
Start to finish: Task B cannot be completed until task A starts

As you can see from the above, all task dependencies have varying relationships to one another depending on the task or project phase.

Unlike project tasks that are independent of one another (i.e., they are not interconnected and do not share resources), finish-to-start task dependencies, for example, describe a sequence of activities where one task must be completed before another begins. An example of a finish-to-start task dependency might be needing to let a cake cool before adding icing.

Another type of dependency is a finish-to-finish task dependency, where one task must be completed before another can also be completed. An example of a finish-to-finish task dependency is a house sale being completed once property inspections have also been completed.

What are the four types of project dependencies?

Generally speaking, dependencies in project management can be grouped into activity-related “buckets” when they relate to overall projects rather than just tasks. These include:

Logical dependencies: Sometimes referred to as causal dependencies, these arise from the inherent sequential nature of work, e.g., a wall must be built before it can be painted.
Resource dependencies: These occur when project tasks require the same resources, such as equipment, team members, or space. When this happens, one task must be completed before the resources can be allocated to the next.
Preferential dependencies: Also known as discretionary dependencies, these are based on best practices or preferences, usually established over time and experience.
External dependencies: These involve relationships between project tasks and external factors, such as third-party vendors, regulatory approvals, or contemporaneous events.

What is an example of a project dependency?

As you can see, there are lots of different types of project management dependencies that will be different depending on the industry or field you work in. Below we’ve put together a table of examples so you can get an idea of how project dependencies might work in a real-life situation.

	Manufacturing	Marketing	Professional Services
Logical	The design team must create a plan and prototype before production begins.	A script must be written before the actors can provide a video voice-over.	An accounting firm must access a company’s accounts to analyze them.
Resource	Raw materials need to be assembled before production can take place.	Two more graphic designers must be hired for a big upcoming project.	Two lawyers must be reassigned in order to attend court for a client.
Preferential	Safety testing must be completed before the product is launched publicly.	A manager must approve all social media posts from the company’s accounts.	It’s best practice to test new software before it’s installed on client machines.
External	Production can’t formally start until regulatory sign-off is delivered.	A campaign is canceled because the product is suddenly recalled.	A large-scale security vulnerability is found in third-party software.

What is the purpose of project management dependencies?

Dependencies are crucial elements of effective project planning. They can clarify the relationships between tasks, ensuring that they follow logically to achieve an end goal. This helps to avoid shortcuts that may negatively impact the overall project schedule, ensuring a uniform, quality-controlled process.

If a project manager can identify and manage dependencies, they will be able to better spot roadblocks and deliver a project on time. When a project manager plots out dependencies, a sequential order of tasks will become clear, generating a streamlined workflow.

If one dependency is missed or delayed, the problem will be immediately apparent as progress will halt. That means any issue can be tackled quickly and definitively before it has time to seriously affect delivery.

What is the difference between external and internal dependencies?

Dependencies can be further broken down into internal and external categories.

Just as they sound, internal dependencies take place inside a team, department, or organization. They might include:

Task-based dependencies: These follow a logical sequence towards completion. For example, you must create an advertisement before you can publish it.
Team-based dependencies: These require collaboration. For example, the legal team and sales team have to work together to produce a binding customer agreement.
Approval-based dependencies: Just like they sound, these require sign-off. For example, you can’t hire a C-suite team member without board approval.
Resource-based dependencies: As mentioned, these relate to resources such as time, people, or capital. For example, a new project can’t start until the team completes its existing work.

External dependencies usually involve elements outside of an organization’s control, such as third-party vendors or even unexpected events like severe weather or civil unrest. Common examples include:

Financial dependencies: Proposed expenditure might depend on a new loan, a stock value increase, or a successful quarter.
Bureaucratic dependencies: A new product often can’t be released until it gets sanctioned by the relevant authorities.
Supply chain dependencies: For example, a boat getting stuck in the Suez Canal can seriously affect global supply, leaving critical deliveries delayed or canceled.
Regulatory or legislative dependencies: A new or changing regulation or law can have a drastic effect on a company’s plans and projects.

Project dependency management tools

So what are dependencies in project management? Well, it’s probably become clear by now that they’re a critical part of modern work. The next question is usually: How can we make managing dependencies easy for busy teams? Luckily, there are a number of useful tools available that can help us visualize, organize, and execute dependencies in a couple of clicks.

The most-used project dependency tools are:

Gantt charts: One of Wrike’s most popular tools for more than a decade, Gantt charts are a great way to see your workflow come to life. Based on a horizontal bar chart, they clearly display a project timeline, complete with due dates, milestones, and the all-important dependencies.

Artem Gurnov

Artem is a Director of Account Development at Wrike. He previously held the role of Project Manager, overseeing a team of customer success managers (CSMs). Over the years of building teams and scaling business processes, he has successfully deployed multiple projects, from automating client outreach to setting up work prioritization tools for sales reps and CSMs.

What Are Dependencies in Project Management?