ISTQB (International Software Testing Quality Board,), defines burndown chart for an agile process as:
A chart that shows the remaining effort against time in an iteration.
The burndown is a graph that displays how fast you and your team are burning through customer’s user stories. It shows the total effort in contradiction of the volume of work we send each iteration. Burn Charts are the very powerful tool and are often used by Agile teams to measure development against estimates, recognize possible dysfunctions, view scope alteration trends and highlight any inherit scheduling risks. Most importantly, they offer a simple yet consistent basis for conclusion making and path modification. This is simple yet effective visual illustration of project progress. It gives us a rough awareness of how we are doing in the present Sprint. Burndown chart can be Most beneficial on 1-4-week Sprints.
Microsoft Excel can be used to generate the burndown chart. Excel offers the maximum flexibility, but other tools like JIRA can also do the same.
Burndown chart is an essential metrics of agile software development method. It is a simple, yet prevailing map that can be used on a daily base for tracking the project progress. A burndown chart is a depiction of effort remaining over a period. The graph has the following details:
1. X- axis is the number of days for the sprint
2. Y- axis is the effort remaining for the sprint
Kinds of burndown charts are:
1. Sprint Burndown Chart
2. Release Burndown Chart
3. Product Burndown Chart
Steps to produce Burndown Chart in excel
Step 1 – Estimation of Effort of the Tasks
Create two columns in an excel workbook having headers as Tasks and Estimated Effort respectively. In the tasks column, list down the tasks. In the estimated effort column, enter estimated effort for to each task in terms of hours.
Step 2 – Plan Duration (as Number of Days) for Sprint
plan the number of days available to release the sprint. For example, you set 10 days for your sprint. Insert 10 columns to the excel table with headers Day 1, Day 2 till Day 10.
Step 3 – Compute Total Estimated Effort
Now calculate the total estimated effort by Adding the values of the rows in the column of ‘Estimated Effort’. During this time, you can also choose an effort level to be applied per day to ensure a constant workload during the sprint.
Step 4 – Calculation of Remaining Estimated Effort
To calculate remaining estimated effort, subtract the total of estimated efforts from total estimated effort of the days.
If Total estimated effort is 80 hours.
To calculate the ‘Remaining Estimated Effort’ at day 2
Add up the estimated efforts of day 1, day 2 i.e. 8 *2 =16.
subtract this from total estimated effort i.e. 80-16= 64.
Thus, the remaining estimated effort at day 3 is 56 hours.
Step 5 – Enter the Actual Effort
As the days pass, enter team’s actual effort for each task in the separate day’s column.
Step 6 – Estimate Remaining Actual Effort
Your actual remaining effort can vary as you start progress on a task. So, you might also require to re-estimate the actual effort required to complete the task.
Step 7 – Insert Chart
After having all data for your sprint burndown chart. It is time to insert a chart and understand the graphical illustration of the project progress.
For this Select the rows of ‘Estimated Remaining Effort’ and ‘Actual Remaining Effort’ and then Select Line with markers option under Line Chart in Insert tab. Then customize the chart accordingly
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Advantages of using a burndown chart are:
• Burndown charts are simple & easy-to-follow
• They visibly present an Agile team’s accomplishments
• Clearly, indicate what the team still needs to accomplish
• Make the certainty of the project clear.
• Demonstrate the influence of decisions.
• Act as an indicator for warning if things aren’t going according to plan.
• Make teams realize if they are on the mark with their targets.
• Alerts the team to possible difficulties or bottleneck conditions
• Teams can understand the necessity to emphasise their efforts to get back on the path.
• Inspire the team Members
• Make team aware of where they have reached till now and effort they still need to do
• Instant understanding of the Sprint work (behind or ahead of theschedule )
• supports in monitoring the improvement by displaying project’s velocity by simple and easily understandable means. Useful to visually compare actual velocity against the estimated velocity to encounter the deadline.
The Disadvantages of using a burndown chart include:
• Does not show what tasks are still in progress
• Do not depict how near the team is to finish their work.
• Unable to judge what are the risks at a specific point in time
• Unable to Identify the risks due to which we are on the agenda or not able to progress etc.
There are numerous Agile tools Like Rally, Version One etc available with in-built burndown chart facilities. Other than these tools, an excel spreadsheet can be used to generate a burndown chart. On the spreadsheet, input the sprint dates on the X-axis and the remaining efforts on the Y-axis.
Burndown Chart answers the following questions:
1. Time the team will take finish the present iteration
2. Time to finish the work
3. Is there any scope creep
Generating burndown charts accurately are vital inside any scrum project. One can either generate burndown charts manually or on task boards, or use any software tool available.