What is a Resource Breakdown Structure (RBS)? A Complete Guide

What is a Resource Breakdown Structure?

A resource breakdown structure (RBS) is a hierarchical chart of resources, often divided by either their type or function, that are needed to complete a project.

It’s important to clarify that resources is a broad term—while this means people by default, it can also extend to anything that incurs costs in your project, such as tools, equipment, materials, fees and licenses, facilities and more.

A resource breakdown structure is designed to help a team allocate its resources efficiently throughout the project life cycle, which is typically presented as a tree diagram or a spreadsheet in its most basic form.

Project managers are often responsible for creating the resource breakdown structure during the planning stage, then maintaining and using it through the project, taking into account insights from other team members and experts.

RBS vs WBS

There is often confusion between the resource breakdown structure (RBS) and the work breakdown structure (WBS) since they both look and sound almost identical, and they are deeply interconnected parts of a project’s success.

The easiest way to tell them apart is their focus:

A work breakdown structure focuses on tasks/deliverables. It answers the question of, “what needs to be done?”

On the other hand, a resource breakdown structure focuses on assets. This answers the question of, “who do we need, and what do we need to get them, so things get done?”

The quality of your RBS is greatly affected by the WBS, and you’ll often find yourself looking at the WBS so you can make informed decisions about what needs to go into an RBS and where.

Key Takeaways

• A resource breakdown structure (RBS) is a hierarchical structure of all assets—including personnel, tools, materials, facilities, and licensing fees—required to complete a project.
• The RBS helps to uncover hidden costs early, mitigates budget and scheduling risks, and acts as a transparent "single source of truth" for stakeholders.
• A key best practice for creating an RBS is organizing human resources by function, instead of identifying specific individuals, making it more resilient against changes in manpower allocation.

Why are Resource Breakdown Structures Important?

Why a resource breakdown structure is important is the same as asking, “why are people and tools important to this project?”

The simple answer is that people and tools are what get the actual work done, not ideas or plans.

The resource breakdown structure helps your project in the following ways:

It allows for resource planning accuracy and budget efficiency. Having a thorough inventory of resources allows you to quickly evaluate costs and helps your team spot potential hidden costs that need to be accounted for. This allows for optimized resource utilization.

This cascades into good risk management. Hidden costs and half-baked logistics can throw project timelines way off-track, which can cascade into more budget and resource availability problems down the line. Having the RBS allows your team foresight into both.

Last and most importantly, it’s good communication and transparency. Living references like the resource breakdown structure ensure that information is always available to the stakeholders that need it, allowing communication to flow without depending on constant meetings and real-time human interaction.

All of this allows the resource breakdown structure to act as a single source of truth, helping your team prepare the necessary resources at the right time, so the project moves as efficiently as possible.

Building Effective Resource Breakdown Structures

Creating a resource breakdown structure is deceptively simple, which also makes it easy to overcomplicate.

To build an RBS that actually adds value to your project, keep the following best practices in mind:

Define a good project scope

This is where the relationship between the work breakdown structure and the RBS truly shines.

The two need to align as best as possible to make it easier to monitor resource allocations, especially between your project team and your finance team. If the finance team uses any standards/codes for different resource categories and transactions, matching those to relevant line items in your RBS makes reconciliation easier for both teams.

Organize, organize, organize

Resources are grouped by function (for human resources) and resource type (for non-human resources)

Roles and functions can further be broken down based on skill level, especially with larger teams. It’s especially important to focus on the role and its requirements, instead of attaching the RBS to specific individuals, because the actual human resources are outside of your control; they could leave the company, go on vacation, or get reassigned, which requires you to update the RBS more frequently.

Focusing on the roles allows you to easily shop for alternatives when the individuals filling those responsibilities become unavailable.

Use your team’s expertise

Your team’s experts help with building a good WBS, which also makes them a natural fit for informing the RBS.

Reviewing plans early and thoroughly with key stakeholders allows you to spot gaps in the plan, identify appropriate solutions, and properly validate them as projects take shape.

The RBS serves as a communication tool, but that communication is lost when the process doesn’t account for it. Having regular reviews with your team ensures that the RBS adds value throughout the entire project life cycle, not just in the project planning stage.

Resource Breakdown Structure Tools

While there is no one-size-fits-all solution to building an RBS, the resource breakdown structure template is often based on some of the simplest tools and formats.

Use our guide below to determine the best resource breakdown structure tool for your needs:

Tree diagram

The tree diagram is the most basic, hierarchical list used in resource management. You start by identifying the end goal/product at the top, then adding branches below to categorize the different resources required to build that vision.

This format works best for small-scale projects and for creating team structures, which often already rely on an established hierarchy within your company.

Spreadsheet

Spreadsheets are great when you have a lot of non-human resources at play and need complex cost computing features.

Project resources such as materials, facilities, and equipment are counted and priced using variable unit metrics (e.g., weight, quantity, etc.) Spreadsheets allow you to set up a unified unit column for vastly different types, then use a separate “unit cost” column to seamlessly compute costs between them.

The freeform nature of spreadsheets also allows you to create granular cost computations, from the entire project down to the individual asset.

Gantt chart

Gantt charts are great for managing many human resources, and the focus on time integrates well with the WBS for project scheduling.

Many project management tools can translate task lists into a Gantt chart, where each task can have one or multiple assignees attached. Coupled with built-in fields like due dates, a Gantt chart becomes optimized for joint scheduling and resource allocation.

Often, you’ll find that a project will require at least two or all three of these formats, especially as it grows in scale. Finding a tool that seamlessly integrates all three formats will be a huge boost to your productivity.

Working with Your RBS and Workamajig

Your work informs the resource breakdown structure, and the insights it provides help your team perform that work more effectively. Having a tool that bridges the two is critical in fast-paced, large-scale work environments.

With Workamajig, the ultimate project management software, you have an all-in-one solution for planning tasks and content, allocating resources, and seamlessly transitioning into campaign launches and performance management. Seamlessly translate plans into actionable tasks, then use built-in collaboration and reporting tools to ensure that your team stays on top of the work, completing tasks and addressing roadblocks along the way.

See Workamajig in action!