How is the Ideal burndown line calculated in Sprint Burndown chart?

[Syed Azam]

Ideal Burndown is one of the line series drawn as part of Sprint Burndown chart on Agile 2.0 & SAFe Sprint Dashboards, It  indicates how the team needs to progress on stories to complete the sprint on time.

Ideal Burndown is a straight line between the start day of the sprint and end day of the sprint, starting from the current scope of the sprint trending to zero on last day of the sprint.

The config/ metadata for the Ideal Burndown is initialized in the ScrumBurndownBaseImpl UI Script and set into seriesConfig object.

The data for Ideal Burndown line is calculated during the load of the dashboard and is implemented in the _generateIdealLine method of ScrumBurndown UI Script.

Following is the gist of, 'How the ideal burndown scores are derived' ?

1. Start date and End date of the ideal burndown line is derived from the start and end dates of scope and scope forecast scores.
2. Start value of the ideal burndown line is derived from the  Last score value of Scope scores and End value is set to 0.
3. Slope function is calculated using the above start date, end date and start, end values. (ScrumChartUtil -> createLineSlopeFunc)
4. Ideal burndown points are derived by masking the scope and forecast points , while the values (y)  are set using the above derived Slope function.

Note : As the ideal burndown is a virtual line and scores are calculated on the fl, It has no specific indicator tied to it, hence drilldown(clickable) is disabled on the ideal burndown line.