Timeboxing

Updated on Jan 21, 2024

Edit

Comment

In time management, timeboxing allocates a fixed time period, called a time box, to each planned activity. Several project management approaches use timeboxing. It is also used for individual use to address personal tasks in a smaller time frame. It often involves having deliverables and deadlines, which will improve the productivity of the user.

In project management

Timeboxing is used as a project planning technique. The schedule is divided into a number of separate time periods (timeboxes), with each part having its own deliverables, deadline and budget.

As an alternative to fixing scope

In project management, the triple constraints are time (sometimes schedule), cost (sometimes budget), and scope (sometimes performance). Quality is often added, sometimes replacing cost. Changing one constraint will probably impact the rest.

Without timeboxing, projects usually work to a fixed scope, such that when it is clear that some deliverables cannot be completed, either the deadline slips (to allow more time) or more people are involved (to do more in the same time). Usually both happen, delivery is late, costs go up, and often quality suffers (as per the The Mythical Man-Month principle).

With timeboxing, the deadline is fixed, but the scope may be reduced. This focuses work on the most important deliverables. For this reason, timeboxing depends on the prioritisation (with the MoSCoW method for example) of deliverables, to ensure that it is the project stakeholders who determine the important deliverables rather than software developers.

To manage risk

Timeboxes are used as a form of risk management, to explicitly identify uncertain task/time relationships, i.e., work that may easily extend past its deadline. Time constraints are often a primary driver in planning and should not be changed without considering project or sub-project critical paths. That is, it's usually important to meet deadlines. Risk factors for missed deadlines can include complications upstream of the project, planning errors within the project, team-related issues, or faulty execution of the plan. Upstream issues might include changes in project mission or backing/support from management. A common planning error is inadequate task breakdown, which can lead to underestimation of the time required to perform the work. Team-related issues can include trouble with inter-team communication; lack of experience or required cross-functionality; lack of commitment/drive/motivation (i.e. poor team building and management).

To stay on deadline, the following actions against the triple constraints are commonly evaluated:

Reduce scope: drop requirements of lower impact (the ones that will not be directly missed by the user)

Time is the fixed constraint here

Increase cost: e.g., add overtime or resources

Adoption in software development

Many successful software development projects use timeboxing, especially smaller ones. Adopting timeboxing more than tripled developer productivity at DuPont in the '80s. In some cases, applications were completely delivered within the time estimated to complete just a specification. However, Steve McConnell argues that not every product is suitable and that timeboxing should only be used after the customer agrees to cut features, not quality. There is little evidence for strong adoption amongst the largest class of projects.

Timeboxing has been adopted by some notable software development methodologies:

Dynamic systems development method (DSDM)

In lean software development, pull scheduling with Kanban provides short term time management. When developing a large and complex system, when long term planning is required timeboxing is layered above.

Rapid application development (RAD) software development process features iterative development and software prototyping. According to Steve McConnell, timeboxing is a "Best Practice" for RAD and a typical timebox length should be 60–120 days.

Scrum was influenced by ideas of timeboxing and iterative development. Regular timeboxed units known as sprints form the basic unit of development. A typical length for a sprint is 30 days. Sprint planning, sprint retrospective and sprint review meetings are timeboxed.

In Extreme programming methodologies, development planning is timeboxed into iterations typically 1, 2 or 3 weeks in length. The business revalues pending user stories before each iteration.

Agile software development advocates moving from plan driven to value driven development. Quality and time are fixed but flexibility allowed in scope. Delivering the most important features first leads to an earlier return on investment than the waterfall model.

A lack of detailed specifications typically is the result of a lack of time, or the lack of knowledge of the desired end result (solution). In many types of projects, and especially in software engineering, analyzing and defining all requirements and specifications before the start of the realization phase is impossible. Timeboxing can be a favorable type of contracting for projects in which the deadline is the most critical aspect and when not all requirements are completely specified up front.

This is also a better structure for allowing for new insights that are developed during the project to be reflected in the end result.

In personal time management

Individuals can use timeboxing for personal tasks, as well. This technique utilizes a reduced scale of time (e.g., thirty minutes instead of a week) and deliverables (e.g., chores instead of a component of a business project). Personal timeboxing is said to help curb perfectionist tendencies (by setting a firm time and not overcommitting to a task). It is also suggested that personal time boxing can create an increased pressure for an individual which will lead to better creativity and focus towards a task.