What are dependencies in project management?

A project is not an isolated event. It consists of various tasks that are interconnected. Therefore, pinpointing and addressing dependencies between them is one of the most critical steps for successful project management.

In this guide, we will define the term “dependency” and identify different types of dependencies in project management. Moreover, we will explain how to manage dependencies and provide examples to help you better understand the matter.

The definition of dependencies in project management

According to Max Wideman’s Glossary editor’s choice, dependencies are “relationships between products or tasks.” Another interpretation they provide determines dependency as “a relation between activities, such that one requires input from the other.”

In simple words, dependencies are relationships between tasks that determine their order in a project. 

Tasks can be predecessors and successors to each other. Furthermore, you can have multiple predecessors for one successor task and vice versa. 

Understanding dependencies is vital for organizing work and preparing a project schedule, as tasks are tied together — and the task order matters. 

In brief, dependencies help you figure out the order of tasks.

Now, you are familiar with dependencies. But what types of dependencies can we encounter during the course of our project?

Let’s find out!

Types of dependencies in project management (+ examples)

After defining dependencies, it’s time to find out which types of dependencies are most common in project management.

Dependencies in project management come in the following variations:

• Logical (or casual) dependencies,
• Resource dependencies,
• Preferential dependencies,
• Hard logic (mandatory) dependencies, 
• Discretionary dependencies,
• Internal dependencies, and
• External dependencies.

Let’s briefly explain what each type entails.

Logical (or casual) dependencies

Logical dependencies (also known as casual dependencies) are indispensable to completing a project — they are fundamental requirements.

🔻 Examples of logical dependencies in project management:

• You cannot delegate a task related to website design if you don’t have a design team. In this case, hiring designers is considered a logical or causal dependency.
• You cannot develop a mobile application without having mobile app developers on your team. Therefore, hiring mobile app developers is required to be able to start your project.
• You cannot translate your website into Italian if you don’t have anyone who speaks Italian on your team. In this situation, hiring Italian translators is considered a logical dependency.

Resource dependencies

Resource dependencies are related to the availability of shared resources and the limited resources you have for your project. 

In essence, a lack of any of the resources can cause delays.

Additionally, if two activities require the same resources for their completion, they are dependent on each other.

🔻 Examples of resource dependencies in project management:

• The progress of the website development depends on a designer team finishing a mobile app design so that they can complete the website development project without getting overworked.
• Launching the new project management software depends on the availability of the software testing team that is testing another application.

Preferential dependencies

Unlike the previously mentioned dependencies, preferential dependencies are not strictly necessary to complete a project. 

However, their purpose in projects is to focus on the quality of deliverables, and the teams often set them.

🔻 Examples of preferential dependencies in project management:

• The chief marketing officer may require one final review before the marketing team sends an email campaign prepared by an intern. This step isn’t necessary as someone from the marketing team also checks newsletter campaigns before sending them to subscribers.
• The quality assurance manager of the software testing team may want to review all resolved tickets before informing the development team that they are resolved. This step isn’t required as well. Every testing department member is responsible for assigned tickets and needs to double-check if everything functions well before marking any ticket as resolved.

Hard logic (mandatory) dependencies

Hard logic dependencies are also known as mandatory dependencies. 

These dependencies are usually legally or contractually required. Furthermore, they can be directed by company procedures or physical limitations.

🔻 Examples of hard logic (mandatory) dependencies in project management:

• You cannot start a construction project if you don’t have building regulations approval. In this situation, getting permission is a logical dependency.
• You cannot buy equipment for your factory from the manufacturer without signing legal documents with the equipment manufacturer.

Discretionary dependencies

Discretionary dependencies are usually established based on best practices. These dependencies reveal there’s more than one path in a task sequence, and they are at the discretion of the project management team.

🔻 Examples of discretionary dependencies in project management:

• Installing the pipes is usually completed before installing the wires.
• Electrical work is generally completed before wall painting.
• It is a good practice to conduct keyword research before writing an article.

Internal dependencies

Internal dependencies are dependencies between tasks or activities within the project. They involve a precedence relationship between project activities.

🔻 Examples of internal dependencies in project management:

• The quality control team cannot test a device until the engineering team assembles it.
• The QA team cannot test software until the development team has finished the development process.

External dependencies

External dependencies are relationships between project and non-project activities. These activities are, in most cases, not under the project team’s control.

🔻 Examples of external dependencies in project management:

• The production process in the food industry may be dependent on the delivery of equipment from an external source.
• The building construction process depends on construction material suppliers.

In addition to these types of dependencies, tasks in project management also have their own dependencies. 

Let’s find out what task dependencies are and how they work.

Task dependencies

Task dependencies are relationships between preceding and succeeding tasks.

They are, practically, the order in which tasks should be performed, and they come in four variations:

• Finish to Start (FS),
• Finish to Finish (FF),
• Start to Start (SS), and
• Start to Finish (SF).

Let’s find out more about every mentioned type of task dependency.

Finish to Start (FS)

In order to start task B, you have to complete task A first.

🔻 Finish to Start (FS) task examples:

• Installing the operating system on a mobile or tablet cannot start until the hardware is assembled.
• Ordering from a website cannot be done until an account is created.
• You cannot receive newsletters from company A until you subscribe to their newsletter list.
• The building & land plan approval must be obtained before construction can start.
• Preparing the landing page design is required before the developing process can begin.
• Road paving must be finished before road marking can start.

Finish to Finish (FF)

You cannot finish task B until you complete task A.

You can work on task B, but will be unable to complete it without task A.

🔻 Finish to Finish (FF) task examples:

• A magazine editor cannot finish her editing work before the writers have finished their articles.
• Software developers cannot declare the feature as developed and ready for production until the QA team has finished feature testing and approved it.
• A marketing intern cannot send a newsletter before the designer has finished the newsletter design.
• You cannot finish painting the walls before finishing the building. You can paint the walls in certain rooms of a building being constructed, but you can’t finish the job until the whole building is built.
• You cannot formally end project “Z” until you transfer deliverables to the client.
• Front-end developers can work on a new product page, but they cannot finish their task until the marketing team delivers all material they want on a particular page.

Start to Start (SS)

Task B cannot start until task A has started.

🔻 Start to Start (SS) task examples:

• A designer cannot begin preparing a text illustration before a writer starts writing an article.
• A project manager cannot assign tasks before assembling at least a few people for the project team.
• The foundation construction process can not begin before the excavation of the foundation starts.
• The food packaging process cannot start until activating the conveyor system for the food packaging line.
• You cannot paint the house before assembling at least a part of the scaffolding.

Start to Finish (SF)

This logical relationship implies that you must start task A before you can finish task B. So, the second activity is dependent on the start of the first one.

🔻 Start to Finish (SF) task examples:

• The building construction must start before the investor can sell apartments.
• The replacement shift worker has to arrive and clock in to start her shift before the existing shift worker can clock off and end his shift. 
• If your company is redoing its website homepage design, it will need to keep the old one while starting developing the new one before it can be replaced.

Now, you know which sorts of logical relationships between tasks you can encounter and what dependencies you can experience during your project. 

So, it is time to learn how to manage dependencies.

How to manage dependencies in project management

There are a few steps you should take to manage dependencies:

• Identify and record all dependencies, 
• Keep stakeholders informed, and
• Monitor risks.

Let’s take a look at what each step entails.

Identify and record all dependencies

The first step is dedicated to the identification of all dependencies between the project tasks and activities. Brainstorm all possibilities with your team, and remember to record them. 

First, you need to identify the following:

• Are there tasks that need to end for other tasks to start?
• Are there tasks that you need to start performing or finish simultaneously?
• Do you need to begin working on some tasks before completing other tasks?

Creating a dependency diagram to visualize the data comes in handy. For example, Gantt charts are convenient for scheduling and prioritizing your project activities.

Identifying task dependencies is the step you don’t want to miss. There are several reasons why you need it:

• Accurately estimating the overall project duration is vital for managing stakeholders’ expectations. 
• Identifying the project’s dependencies is critical to precisely estimating your project’s duration.
• If you don’t know how tasks and activities are related to one another, you won’t be able to act appropriately if anything unexpected happens.

You can use a critical path method to identify all the tasks your team must complete to finish a project on time. Critical path is important as it shows the most sensitive dependencies in a project. 

According to the Harvard Business Review, a critical path method:

“provides a means of determining which jobs or activities, of the many that comprise a project, are “critical” in their effect on total project time, and how best to schedule all jobs in the project in order to meet a target date at minimum cost.”

So, take your time to think about logical relationships between tasks, as this step is critical for your project’s success.

Keep stakeholders informed

As a manager, you must ensure project stakeholders understand the dependencies between tasks and activities and how they can affect the project. 

Communicate regularly with them and make sure stakeholders know how tasks are connected and what is the critical path in the project. 

To ensure timely communication, you can invite them to join a dedicated business chat app channel your team uses for daily communication. 

We recommend Pumble as it has a guest access option. Invite vendors, contractors, clients, or any other stakeholders to join discussions, and give them limited access to your channels.

It’s easy to use, and you can have all the messages with project stakeholders in one place.

Monitor risks

You have to ensure that the project remains on track even if something goes wrong. Understanding risk dependencies can help mitigate risks. So, look at each dependency and brainstorm possible risks.

You need to comprehend how they can affect your project if something unexpected occurs and the risks for your project overall. And you have a tool to do that: your risks register. 

Project risk management helps you deal with threats and control the damage.

Now, when you know how to identify and manage dependencies, you can focus on getting things done.

Wrapping up: Take your time to identify all dependencies in your project

Just as you cannot make a cake without following the right order of the steps in the baking process, you cannot organize your project tasks if you are not aware of their relationships. Imagine putting a glaze on the cake crust before the filling. No one does that.

The same logic can apply to projects. You must identify which tasks are dependent on others and the order of their execution. 

So, take your time to identify and record all dependencies. By doing that, you will be able to carry out your project successfully.

It’s not that complicated. Use our guide to help you determine the types of dependencies you can encounter on your project management journey.

References:

• Levy, F. K, Thompson G. L, and Wiest J. D.(n.d.). The ABCs of the Critical Path Method. Harvard Business Review. Retrieved February 10, 2022, from https://hbr.org/1963/09/the-abcs-of-the-critical-path-method
• PRINCE2.com. (n.d.). What are dependencies in project management? Retrieved February 8, 2022, from https://www.prince2.com/eur/blog/project-dependencies
• Usmani, F. P. (2021, July 13). Project Management Dependencies: Types, Examples, and Explanations. PM Study Circle. Retrieved February 18, 2022, from https://pmstudycircle.com/project-management-dependencies/