What is a WBS project structure?

The basis of project planning is the compilation of a structured list of works, the implementation of which allows you to achieve the goals of the project. To do this, a tool known by several names is used:

Work Breakdown Structure (or WBS-structure)

in USA is the Structural Breakdown of Project Work (WBS) or the Hierarchical Work Structure (DPI).
The essence of decomposition is the division (division) of the process into parts according to one or another feature: by the type of product produced during the work, by functionality, by stages of the life cycle, etc. It is important that such a division highlights fairly simple components - more manageable elements that help to better control the implementation of tasks and the achievement of the goal. However, the hierarchical structure of work differs from just an implementation schedule, from a document similar to a project plan and from a list of milestones. What exactly is different, we will consider in the article.

Definition and Characteristics of WBS

Work Breakdown Structure.

Work Breakdown Structure is a representation of the project, executed in the form of a hierarchical structure of work, which is achieved through sequential decomposition. The tool is aimed at detailed planning, cost assessment, determination and distribution of personal responsibility of performers, etc. – that is, on the main works and results that determine the content of the project.

In Work Breakdown Structure, project elements can be a service, product, work, or wbs group. Each lower level in the hierarchy details an element of the higher level, but the following principles must be observed:

The "Right Tree" principle. The idea is that each dependent element (each "branch" or, in an even more fractional separation, each "sheet") has only one parent element.
The principle of completeness and logical harmony. The SDR should take into account all elements of the project, but nothing should be duplicated.
The principle of uniformity of the criterion. The decomposition process should occur according to one criterion, therefore, for example, it is impossible to work interspersed with both the product and the functional tasks at once.
SDR Depth Principle. Separation should be made until the resulting structure is easily manageable and controllable. Most often, this process ends when structuring to the level of elementary work – one that one employee is able to perform, or which can be controlled as a separate unit.

The embodiment of these principles in the project leads to the fact that the hierarchical structure of work acquires certain characteristics, namely:

always describes the content of the work with the necessary (sufficient) accuracy,
covers the entire volume – 100% – of the work on the project (if some works are not included in the SDR, then they fall out of the content),
the structure is decomposed into hierarchically arranged elements (packages, sub-packages, etc.)., with the upper levels corresponding to the main stages of the project, and as we approach the lower levels, the definition of work becomes more detailed,
blocks of works in the structure are autonomous,
works have a measurable (or comparable) result, and each block of work has an initial result (while easily estimating time and costs),
the starting and closing activities are defined clearly and unambiguously.
Thus, each subsequent level of decomposition consistently details the content of the project, which makes it possible to assess the volume of work performed, the amount of money spent and the timing of implementation.

At the same time, the lower levels of work packages correspond to relatively small amounts of work, which simplifies the assessment of performance parameters, and also helps to clearly identify the actions that lead to the achievement of project goals. This approach forms the basis for establishing cost and labor intensity as measurable indicators.

Algorithm for building a hierarchical structure of work

In practice, in the process of forming a Work Breakdown Structure, you need to be able to correctly raise questions and competently organize the structuring process. To do this, at the initial stage, various algorithmic variants are proposed that describe the top-down method for creating a WBS.

Example No. 1:

Based on the definition of the scope of the project coverage, the objectives of the project are written.
The row (horizontally) lists the initial results that you need to get to achieve your goals.
For each individual initial result, the necessary or key blocks for its operation are determined.
In a vertical column, they are detailed to the required degree of detail.
Team members and all interested parties are involved in the work on the project. (As an option, the development of SDRs is carried out immediately by the joint efforts of the participants).

Example #2 using stickers and flip chart:

Project participants working in a team need to know what they think is needed to implement the project.
All the answers to this question are recorded by the project participants on stickers.
Close and concurrent answers about the most significant tasks are grouped into stacks or hung on a demonstration board in thematic columns.
Those tasks that did not fall into any column are glued separately.
Columns or stacks with grouped tasks are given names that are written to the flipchart (with the appropriate set of stickers under each category).
Next, the final results are divided into operations, and this cycle continues until it becomes possible to track and control individual tasks. It is important that one work package contains one result.

If project management programs are used in the creation of work Breakdown Structure – for example, the most common MS Project or its analogues – then:

The final goal of the project fits into the task name field.
After evaluating the final results and compiling a list of them, all sub-results are shifted to the right so that one final result consists of their set.
The final results are broken down into operations. For each sub-result, a different list of operations is compiled. This action is repeated until the scope of the work package is reached. In this case, the shift to the right forms links between the results and their sub-results. (MS Project creates an SDR code automatically in the structural number field, which changes when the task moves to another level).

Структурная декомпозиция работ(пример)To embed WBS in a project schedule, you need to add the following information to the previously created hierarchical structure:

The duration, or full time, of each task.
Dependency and relationship between tasks, which can be established by using a network diagram.
Restrictions for each task (if any).
The start and end dates of the task (when you specify the duration parameter, the program calculates these dates automatically).
Resource names.
Since work can be decomposed according to different criteria, it is important to ensure that the criterion approach necessarily covers the entire scope of the project. Sometimes a mixed approach is used, when different decomposition criteria are chosen at different levels: at the first - the phases of the life cycle, at the second - organizational structures, at the third - key results.

WBS as a management tool in various project manifestations

The structural decomposition tool can be effectively used in various design manifestations:

To determine project results.
For the organization of communications. WBS helps to carry out a directed transfer of information, taking into account the task and responsibility of the participant for its implementation.
For documentation and reporting. Documentation of WBS is manifested in general terminology, in the formation of the budget "top-down", in the preparation of separate reports corresponding to the structure of the WBS.
To optimize the management and typing of levels. So in the thematic literature it is recommended to use no more than 6 levels, where the upper 3 are intended for customer-level information, and the lower 3 - the level of the performer. But, first of all, the depth of detail should be focused on the complexity and size of the project.
The hierarchical structure of work can be both developed "from scratch" and include components of previously created WBS structures, which are taken from previous similar projects, template standardized options used by the organization, taking into account the success of their application in the past in typical conditions.