The Rolling-Wave planning technique
"You don't have to see the whole staircase, just take the first step." - Martin Luther King Jr.
Following Martin Luther King's famous quote, the focus of this article is on taking the first step before seeing the whole picture. Indeed, recognizing that not all the aspects of a project can be fully defined or known at the starting stage, the Rolling-Wave planning allows the progressive elaboration of all the details as far as the project goes on. The project management profession has used the term Rolling-Wave referring to the expression "plan a little, do a little" to characterize its use of iteration along the project lifecycle.
As stated in The PDMA ToolBook 3 for New Product Development, flexibility is one of the most important cornerstones whenever considering project planning. Moreover, in new product development, most management approaches presume a high ratio of knowns to unknowns, and most planning defines prescribed pathways through developmental stages and decision gates . At the same time, project environments reflect a very low amount of information at the beginning of the project, when the decision's importance is more relevant, while it increases as the project lifecycle is developed.
To counter this paradox, the Rolling-Wave technique is one of the newer agile tools that has been widely adopted as it yields benefits of improved speed, flexibility and customer value. Rolling-Wave is a robust, sophisticated way to manage the risks of innovation, adapt to change, align the organization, and align the team towards breakthrough results .
This article aims to contribute to the profession of project, program and portfolio management in:
- Understanding the purpose, importance and principles of The Rolling-Wave technique.
- Identifying its key characteristics and major aspects.
- Recognizing its boundaries and limitations.
Developed by Gianluca Santinon
Overview of the Rolling-Wave technique
Innovation and product development projects have environments characterized by many unknowns and rapid change. Recently, an emerging set of practices termed agile product development has caused traditional orthodox product developers and project managers to rethink their approach to creating fast and flexible projects . Project environments nowadays are evolving rapidly and business systems have become increasingly complex to optimize cost, quality, timeliness of results and comply with variations in regulations in the marketplace . In this context, the agile approach has become more and more popular, underlining the key to success for each project. The traditional linear waterfall approach has been overcome by the need to be flexible and agile. As mentioned in The PDMA ToolBook 3 for New Product Development, an agile enterprise rapidly adapts to changing business challenges and opportunities. Agility has always been important for an enterprise to achieve and maintain competitive advantage. Agile organizations can quickly anticipate change as well as react to the unexpected. With this agile capability, these organizations can create value and do it with speed and flexibility  .
In these situations where the conditions are intricated and not easily predicted, the Rolling-Wave is revealed to be one of the agile techniques that offer clear benefits and permits overcoming the brittle schedule problem towards alternative robust planning. Defining a brittle schedule as a project that breaks easily due to a change in assumptions, the alternative robust planning can be seen as a project model that can withstand the stresses of change in the project, adapt to changes and serve to focus the project's success. A robust plan is a useful tool for the project team to align and integrate its efforts to achieve a project characterized by speed, flexibility, and customer value added .
PLAN A LITTLE, DO A LITTLE
The term Rolling-Wave is intended as an iterative approach that can be described using the expression "Plan a little, do a little". Dealing with an unclear picture of the whole project, as shown in Figure 1, the Rolling-Wave technique permits focus on iterative work and frequent updates to the project plan. It permits to focus on what is known, "Plan a little", and work on it, "do a little", until more information becomes available and other data is relevant, so it is possible to evaluate the next "wave" . It is therefore a project planning technique for projects that don´t offer all the data needed to create a plan or a schedule up front: the project plan evolves as more details become clear. In this context, "plan a little" means to create a rough plan for the next wave of work, while "do a little" means to execute the current one. This approach allows the team to move forward with the work for which there is enough data to ensure a clear understanding. Simultaneously, it is also possible to plan the future work that has still to come. As the project goes on, it is possible to gather more information and refine the plan: the key point of the Rolling-Wave planning underlies this step where the team can adapt and refine the plan eventually considering any changes or new information encountered along the way.
In essence, "plan a little, do a little" is a balance between what is planned and the actions that can be taken, with an emphasis on flexibility and adaptation. This approach allows for a continuous feedback loop where the team can adjust their plans based on what they learn in the execution phase, improving the overall outcome of the project.
The Rolling-Wave technique: three main principles
To apply the Rolling-Wave planning and understand the benefits that this technique can take advantage of, it is important to describe the three main principles that undergird Rolling-Wave´s effectiveness .
Principle One: Project and Product Architecture
An architecture defines the basic structure of a system, it defines the chunks of a product and project work. Good architectures allow the team to keep a big-picture perspective even as they drill into details. Good architectures provide a basis for assessing priorities and aligning activities. The result is improved development speed and flexibility. Product and project architecture are fundamental to formulating a Rolling-Wave approach .
- the arrangement of functional elements;
- the mapping from functional elements to physical components;
- the specification of the interfaces among interacting physical components to meet the desired goals and requirements.
Defined what is the architecture of a product, accordingly to "The PDMA ToolBook 3 for New Product Development", it is essential to highlight that interfaces are common failure points and, therefore, understanding their structures, functions and limitations can help to manage interface issues and avoid substantial frustration, rework and delay.
For instance, a well-designed product interface enables team members to work together more efficiently by providing a clearer overview of the project, its goals and objectives. In this way, the team members can have a shared understanding of the project, reducing the time needed for communication and collaboration. In the same way, a good product interface provides real-time access to critical project data, which can help team members make faster and more informed decisions.
Overall, a well-designed product interface can help improve the speed and flexibility of a project, making it more efficient, adaptable and successful.
Project architecture, instead, refers to the overall project planning strategy covering topics such as team composition, level of authority, review and approval cycles, roles and responsibilities, risk and issues analysis approach, escalation strategy, etc. In this case Rolling-Wave is best suited for practitioners who have a basic understanding of standard program/project management concepts and principles as it fosters an integrated appreciation of these structures .
For example, "Plan a little, do a little" works best when the team has the capability for seeing the big picture and the details so that the project can balance the top-down perspective to the bottom-up .
In particular, the top-down approach is consistent with the idea that top management must have strict control over the organizational knowledge and, consequently, they must set the goals in line with the overall strategic direction for the company. This implies a pre-defined and clear vision of knowledge in the company, as well as about the strategic goals. In a top-down approach, the ultimate users, at any level of the organization, will therefore simply use it in the way that is prescribed by the top-management . Conversely, a bottom-up approach implies that the employment and configuration are strictly dependent on the real needs of the users. A bottom-up approach takes the view that valuable organizational knowledge should be shared by users in a sort of social community, and not controlled by the management .
The next video provides a further explanation of the differences between top-down and bottom-up planning:
Balancing the two approaches means having employees at any level of the organization that, depending on the specific time through the project lifecycle, can either simply perform what has been decided by the top management or are directly part of the decision-making process, as illustrated in Figure 2. To be a successful planning technique, the Rolling-Wave has to be managed by teams that possess a combination of skills and allow them to view the project holistically, from both a top-down and bottom-up perspective.
In general, considering the project lifecycle, the proportion of top-down thinking is greatest at the beginning and then diminishes towards the completion of the project.
Overall, talking about the project architecture, the Rolling-Wave achieves agility because it encourages both a strategic perspective and tactical control over the day-to-day work.
Principle Two: Uncertainty and Ambiguity
The Rolling-Wave planning technique is used in project management to deal with uncertainty and ambiguity. Uncertainty means literally without certainty and this implies a lack of predictability of structure and information. Ambiguity, instead, refers to a scenario where more than one outcome is possible.  
Trying to investigate in detail the levels of uncertainty, it is possible to split them into four main categories: technical, market, organizational and resource.
- Technical uncertainties relate to the completeness and correctness of the scientific knowledge, the extent to which the technical specifications of the product can be implemented, the reliability of the manufacturing processes, maintainability and so forth .
- Market uncertainties refer instead to the degree to which customers need and want the product, the value creation and competition. They have to deal with customer acceptance of the proposed functionality, feature set and price. Here can be found all the decisions regarding the extent to which conventional forms of interaction between the customer and the product can be used, the appropriateness of conventional methods of sales/distribution and revenue models and the project team’s understanding regarding the competitiveness with competitors .
- Organizational uncertainties involve organizational issues both within the project and between the project and its various internal and external constituencies. The firsts are related to organizational resistance, lack of continuity and persistence, inconsistency in expectations, changes in internal and external partners and changes in strategic commitment. On the other side, there are also uncertainties related to the conflict between the team project and the other units engaged: these are referred to the difficulty of managing the relationship between them .
- Lastly, resource uncertainties refer to the project teams' struggle to attract the resources they required. They refers not only to financial resources but also to competencies. Moreover, even when a breakthrough project team is formally established, its funding is generally unstable over time: interest in the project and sponsors come and go. This category is usually closely associated with technical uncertainty.
The greater each of these types of product development uncertainty, the more the program needs to use techniques that foster agility, such as Rolling-Wave.
Principle Three: A functioning team with good leadership
Experts in new product development have long regarded personal leadership and effective teamwork as key success factors . Indeed, team effectiveness will also lead to better collaboration and communication between team members, which is essential for effective Rolling-Wave planning.
The use of cross-functional teams is a common practice as managers find ways to create a more responsive firm. Members from diverse functional areas contribute unique perspectives to cross-functional teams, which can create innovative teams well-adapt to problem-solving . Cross-functional teams are becoming popular not only to include different perspectives when facing new problems, but also to incorporate the customer's point of view and anticipate future problems. Indeed, increasingly for businesses that are adopting agile tools, the development teams are including a knowledgeable representative of the customer as an effective member of the team. This provides relevant feedback on the feature and functions that produce the most value. Because customers can change their priorities, flexible approaches take that dynamic as a given and work to react quickly and effectively . Insiders can accelerate the development of the team as effective project reviewers by participating on an oversight board with outsiders who have long and deep experience with decision-making under uncertainty.
On the other hand, leadership in cross-functional teams is not determined by a single, authoritative position but rather by the abilities of members to collaborate at any given moment. The elements of a team environment work collectively to create a team context that encourages members to provide leadership and accept the leadership of other members .
Therefore, the importance of the team members is strictly related to the effectiveness of the team itself and also to the ability to create an effective team context.
Implementation of The Rolling-Wave technique
To implement the Rolling-Wave technique, it is needed to follow six steps while keeping in mind the three principles behind it previously described. Indeed, project and product architectures, uncertainty, ambiguity and a functioning team with good leadership set the foundation for planning a little and then doing a little.
The steps illustrated in Figure 3 are presented as a guide to applying the Rolling-Wave technique:
Step One: Get the team and strategy in place
The goal of the first step is to get the team a strategy right to achieve and maintain a robust approach. Thus, Step 1 ensures a charter, an approach to capture and manage requirements, the right people committed to the team, and a good project vision.
The project charter is a document that formally authorizes the beginning of a project and provides the project managers with the authority to start project activities. It outlines the purpose and objectives of the project, the scope of work to be done, the key stakeholders, the resources required and the estimated timeline for completion. It also gives the team resources and the authority to use those resources.
If the organization is not ready, it is needed to invest some effort in organizational development or rethink the strategic intentions in light of the organizational capabilities.
Step two: Perform Top-Down planning, starting with Level 1 of the Work Breakdown Structure
Step two establishes the tasks and deliverables for the project. The common tool for organizing and managing the project’s work scope is the Work Breakdown Structure (WBS).
A WBS is a deliverable-oriented hierarchical decomposition of the total scope of work to be carried out by the project team to accomplish the project objectives and create the required deliverables .
In this way, the waves become the planning horizons in which the project will plan a little and do a little. Therefore, project team members should be able to estimate the close-in work with a higher degree of accuracy, decomposing in detail the work within the near-term wave, while, at the same time, longer-term activities are roughly estimated.
Step three: Decompose the first set of "Plan a Little" activities
Since the Rolling-Wave technique uses a Plan a little, do a little approach, the team defines the work packages just for the first time horizon. Indeed, while in this step there is a focus on the first of the branches, the work breakdown structure should include also the work that might occur in the later horizons. In this step, it is only necessary to have a general and conceptual understanding of the work involved in the current wave: as shown in Figure 4, the goal is to detail the right work at the right time as the project advances in cycles of plan a little, do a little.
Step four: The baseline
Step four regards the creation of a baseline. A baseline is a committed scope, schedule, budget, risk, etc. against which the project team will monitor its actual performance . The project manager establishes the baseline together with the executives, sponsors, users, project managers and participants. With the new data, it is, therefore, possible to refine estimations and assumptions, keeping in mind that the most important work of the project team is uncertainty and ambiguity reduction.
Step five: Execute the planned work
In this step, the focus is inside the wave: teams work on the tasks assigned previously and the project manager monitors and tracks their progress and performance. The iterative nature of plan a little, do a little fosters knowledge capture for application in future phases. This learning allows the team to anticipate and avoid future problems, or to react quickly to the risks that the team decides to accept.
Step six: Iterate through the planning horizons and close the project
The last step involves the continuing iteration of the plan a little do a little approach until the end of the project is reached. The iteration will include the assessment of the team’s learning, the needed work and the planning of the next project’s horizon (refer back to Step 3).
As the project completes work in the current wave, the attention paid in the next phase increases, rolling through the entire project. Furthermore, a decomposition of the work breakdown structure and the addition of further details as time and cost baselines will be refined. Projects are completed when the product meets the customer’s requirements and when it has completed the necessary administrative processes demanded by organizational policy.
Benefits and Shortcomings of the Rolling-Wave planning
The use of the Rolling Wave technique helps to overcome the problem of uncertainty in the decision-making process by postponing the decision to a point when all the necessary knowledge is available. However, some disadvantages that can arise when using this project management tool. The benefits and shortcomings of the Rolling-Wave technique are summarised in the following table:
|Its agility allows fostering knowledge capture for application in future phases, anticipating and avoiding future problems, reacting quickly to the risks that the team decides to accept||
Requires project team’s understanding and acceptance of the agile principles
|It shortens the duration of front-end planning and gets the individual work teams started with work sooner||
Not adapt to routine NPD projects where there are few unknowns/incremental innovations
|Improves the sense of ownership and accountability among team members||
People have to be self-disciplined and committed to communicate with their teammates
|Promotes an open-minded and flexible project environment||
Requires trust between people involved
Closing Remarks and Video Illustration of Rolling-Wave Planning
The following video summarises all the topics covered in the article. It also includes a general idea of how the Rolling-Wave planning technique can be used in real life:
There are some references suggested for a further reading regarding Rolling-Wave as a project management tool:
Project Management Institute, Inc. (PMI)., "The PDMA ToolBook 3 for New Product Development", 2008 The PMI provides the standards needed to understand the Rolling-Wave planning. The book identifies project portfolio management principles and performance management areas generally recognized as “good practices” for organizations with business needs to manage complex and intense program and project investments effectively. It has been used as the main reference to write this article since it details a valuable framework for applying the technique, including principles, steps and recommendations.
Mark P. Rice, Gina Colarelli O'Connor, Ronald Pierantozzi,"Implementing a Learning Plan to Counter Project Uncertainty ", MIT Sloan Management review, Winter 2008 This article offers an interesting guide for implementing a Learning Plan. In particular, it has been used for analyzing the four categories of uncertainty that can be observed when dealing with lack of predictability, like New Product Development scenario.
Additionally, the following wiki articles provide a relevant contribution to support the claims and ideas presented:
This article focus on the concept of product architecture and modularity.
The topic of this article covers the concept of project vision.
The WBS has been analyzed and discussed in this article providing references also an explanation for the needed WBS dictionary.
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 Project Management Institute, Inc. (PMI)., "The PDMA ToolBook 3 for New Product Development", 2008
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Mark P. Rice, Gina Colarelli O'Connor, Ronald Pierantozzi,"Implementing a Learning Plan to Counter Project Uncertainty ", MIT Sloan Management review, Winter 2008
- ↑ Larman, Craig, "Building the Agile Enterprise", 2004
- ↑ AXELOS, "Managing Successful Projects with PRINCE2",2017
- ↑ 5.0 5.1 Karl Ulrich, "The role of product architecture in the manufacturing firm", Massachusetts Institute of Technology, Sloan School of Management, December 1993
- ↑ 6.0 6.1 Ana Latorre Duque, Modularity and Black-Boxing, http://wiki.doing-projects.org/index.php/Modularity_and_Black-Boxing#Modularity_in_product_architecture
- ↑ 7.0 7.1 Bolisani Ettore, Scarso Enrico, "Knowledge Management and Organizational Learning", Volume 3, 2017
- ↑ 8.0 8.1 Project Management Institute, Inc. (PMI)., "A guide to the project management body of knowledge (PMBOOK Guide)", 2021 (Seventh Edition)
- ↑ 9.0 9.1 Josh Daspit, C.Justice Tillman, Nancy G. Boyd and Victoria Mckee, "Cross-functional team effectiveness", Team Performance Management, Vol.19, 2013
- ↑ 10.0 10.1 Githens, G. D., "You can’t be done if you don’t know what done looks like!", PDMA Visions Magazine, (January) 2004
- ↑ Kristoffer Glahn, Project Vision Statement, http://wiki.doing-projects.org/index.php/Project_Vision_Statement
- ↑ 12.0 12.1 Project Management Institute, Inc. (PMI)., "Practice Standard for Work Breakdown Structures", 2019 (3rd Ed.)
- ↑ 13.0 13.1 Work Breakdown Structure, http://wiki.doing-projects.org/index.php/Work_break_down_structure_(WBS)