15.4 Agile concepts and techniques
15.4.1 Burn charts
One of the most popular techniques in agile environments is to display progress using graphs. These graphs are known as burn charts and they come in two forms: burn-down charts and burn-up charts (see Figure 15.1).
22.214.171.124 The basics
Burn-down charts are the most well known and they are used to show how much work remains whereas burn-up charts are slightly more complex and they are used to show how much work has been done. Both types of chart aim to provide two important pieces of information:
- What is the situation regarding progress – i.e. what is the current situation and what should it be?
- At the current rate of progress what will be the situation at the end of this time period (which could be a sprint, release, stage, project or any other period of time)?
Typically the vertical axis shows the amount of work to do in terms of effort and the horizontal axis shows time in some form such as days or dates.
126.96.36.199 How a burn-down chart works
In its most simple form the burn-down chart has two lines (see Figure 15.1): a straight line that shows where the ‘ideal’ rate of progress should be (in black on the figure), and a line that is updated on a regular basis (usually daily) that shows the amount of work done (in purple on the figure). The work remaining is shown by the end of the purple line. When the purple line is above the black line this means that work is behind schedule. If the purple line is below the black line this means that work is ahead of schedule.
The current rate of progress can be determined by the trend of the line (i.e. its gradient) showing effort remaining. This is commonly referred to as ‘velocity’ by the agile community. Assuming that there is stability and constancy in the team, this can then be used to project forward and forecast when the work will be complete and importantly determine if the deadline is likely to be met.
188.8.131.52 How a burn-up chart works
One limitation with burn-down charts is that they assume the amount of work does not change. This is not a significant limitation in most situations (e.g. where a 2-week sprint has been agreed and locked-in/baselined) but if the amount of work is likely to change, or does change, then this will not be picked up by a burn-down chart easily, and therefore a burn-up chart should be used (see Figure 15.1). The purple line shows work completed, which can now be used in tandem with the red line showing the total amount of work. The work remaining is therefore the difference between the red and purple lines. Any work that has been added or removed during the time period can now be seen by the red line.
184.108.40.206 Further information
The reason why burn charts are so prevalent in agile environments is because agile is based on what is (or is not) being delivered and where time and the team size are fixed. Therefore to monitor progress, an agile delivery team (or team manager or project manager) will focus on what, of the planned work for a specific time period, has been completed. Depending on the level at which this work is taking place this could refer to such things as requirements, user stories or tasks.
The recommended way to display a burn chart is for it to be physically mounted on a wall or board and updated manually. This intentionally creates a simple and tactile way of showing and interacting with the information regarding progress. It is not always possible to do this, such as when teams are distributed. However, the temptation to move to capturing and displaying the information electronically should be taken carefully as the benefits of the technology may not outweigh those of the physical engagement created by the tactile experience.
220.127.116.11 Hints that may prove useful
When updating a burn chart, only record information according to completed work. If a 2-day task is 50 per cent complete do not mark anything as completed on the burn chart. The same applies even if it is 95 per cent complete.
Burn charts are less accurate if the size of the tasks being reported on are relatively large for the given time period (e.g. a 5-day task in a 2-week sprint). When working in an agile way it may be appropriate for teams working in sprints (which should last no more than 4 weeks) to break down tasks to a size that needs only a few days of effort or less. Primarily this is needed in order to help make it easier for a team to organize its work. A desirable side-effect of this is to make burn charts more sensitive (to issues/impediments) and accurate. However, there is an overhead with this as time needs to be spent breaking down work into smaller work items.
Either type of burn chart can be used in a wide variety of situations throughout a project. They can be applied to anything that involves time lasting from a few hours, to many months or years.
Make sure the axes reflect the correct units being used. The left-hand axis will typically show effort in the form of points such as story points. However, this needs to reflect the units used when the work was estimated.
15.4.2 Information radiators
When entering a room where an agile team is working you would expect to see lots of information displayed on the walls or boards and you would also expect to see this information conveyed in a ‘low-tech’ style with the abundant use of sticky notes, large sheets of paper, colour, symbols, pictures and graphics.
Information radiators include or are similar to information displays, big visible charts (BVCs), team boards, Kanban boards.
18.104.22.168 The basics
One of the best ways to convey most information is visually, and if it can be accessed quickly then this is even better. If a room contains large sheets of paper or large whiteboards and the information on them can be seen clearly from a distance, then this creates a ‘push’ of information that can be accessed immediately. If information is held on someone’s desk or computer it is not immediately accessible and also needs to be ‘pulled’.
Furthermore, and of similar importance, the creation and maintenance of this information is best carried out manually – i.e. physically writing on charts and moving sticky notes. This can happen very quickly and in any format or style that is felt to be appropriate. For example spontaneous annotations and informal codes and symbols such as ticks, crosses, red dots, green stars, etc. can be used. Although this can be achieved electronically, and perhaps it can be printed off, this takes longer and can be seen as being sterile and not as engaging as the ‘low-tech’ option.
22.214.171.124 Further information
Transparency (or visibility) is one of the key behaviours that is at the heart of most agile approaches. It is a hugely significant part of agile and the use of visible information, handcrafted, simple to understand and instantly available to digest, contributes significantly in this area. The idea is to make information visible to all and understood by all. However there is a risk that comes with this. In order to be fully, or truly, transparent all information about a project needs to be visible and that includes displaying information that may at times be negative as well as positive. This is where another key value which is also at the heart of most agile approaches (and perhaps at the heart of manage by exception) can be enhanced: that value being trust. The opposite of this is when the information is massaged which is sometimes referred to as ‘gaming’.
126.96.36.199 Hints that may prove useful
A good guide to help with deciding on the correct size, format and layout of anything being displayed is to see if the information can be digested by someone walking past. In other words, does someone need to leave their desk and walk over to the information in order to be able to read it? This is why words like ‘big’ and ‘large’ are used to describe these figures and charts. Many people use the abbreviation BVC which stands for ‘big visible chart’.
A wide variety of information can be displayed using this approach. The most commonly displayed information relates to work and how it is progressing (e.g. a burn-down chart or a WIP (work-in-progress) board). Other information commonly displayed would cover quality and defects, risks and issues, vision statements (or similar) and working practices (see Figure 15.2).
Information displayed this way needs to be regularly updated and it will not update itself! Holding a daily stand-up meeting by these displays, and moving the information across immediately, is one way to achieve this.
If a project management team is not co-located this is hard to recreate, but technology, webcams, digital photography and virtual systems can go part of the way to achieving some of the benefits that this brings to how the team communicates.
Do not underestimate the positive impression these graphs and charts give off simply by their attractive appearance!