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New Burndown Chart Problem?

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Michael
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Michael asked on 21 Aug 2015, 12:50 PM

Hi,

could someone explain me this new chart in detail please? See attachment... I am using the burndown mode "Task work remaining"

I suppose the "removed work" is the sum of the removed hours from asks' "remaining hours".

What about the "work done"? My team updates their time sheets on daily basis and to the respective tasks. They also change the "remaining work" daily. But in my burndown chart this is not reflected. Am I understanding something wrong here?

The forecast is also a horizontal line which does not seem to be appropriate.

I am also missing the "optimal" line which I am used to :)

 

However, the second screenshot (entry point:status) looks fine whereas the forecast is wrong as well (This is not our first sprint in case the forecast is calculated based on previous sprints)

 

If I change the burndown mode to "Task estimate" then I get attachment 3 which is indicating a complete other "done work"!

Could someone shed some light on that for me?

 

 

 

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Valeri Hristov
Telerik team
answered on 24 Aug 2015, 09:12 AM
I will try to explain:

Every day TeamPulse generates history records for all changed work items. Those records are used to build the so called historical reports: Burndown and Status History. Each record is a snapshot of all properties of the changed work item.

The Burndown report determines what is the latest snapshot of all existing work items, for each day of the report, filters the results using the chosen criteria and then aggregates some of the properties, depending on the Burndown Mode. Work Items in the status group Excluded (Status=Deleted for example) are not counted.
- Estimate sums the Estimate property of all Work Item types, except Task
- Task Count counts Tasks (and ignores all other Work Item types)
- Task Estimate sums the calculated PERT of the Tasks (and ignores all other Work Item types), using their EstimateOptimistic/Probable/Pessimistic properties
- Task Work Remaining sums the WorkRemaining property of the Tasks (and ignores all other Work Item types).

For Today, we add one more point, calculated from the current state of the Work Items.

To build the chart we perform two calculations - one for all work items (depending on the Burndown Mode) regardless of their Status (e.g. Totals) and one for work items that are in the Not Started and In Progress status groups (e.g. Not Done). The Not Done data is used to draw the Work Remaining line and the Done bars (green). The Totals is used to draw the Added/Removed (orange) bars.

Now when you pointed it, I think that the green/orange bars should not be displayed when Burndown Mode = Task Work Remaining because the calculations are based on the Status and are not correct.

The Forecast is calculated using only the chosen iteration (past iterations are ignored). It calculates the Velocity from the iteration start until Today:

V = (Not Done Work in the beginning - Not Done Work today) / Days from the Beginning

then estimates what will be the work remaining for each day until the end of the iteration, based on the Velocity.

We slightly changed the way the charts work in order to fix a few bugs, and not all charts in TeamPulse are using the new API, hence there could be differences in the UI. We will be updating them in the future as we remove the old code.

Regards,
Valeri Hristov
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Michael
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answered on 24 Aug 2015, 09:30 AM

Thank you Valeri.

However, I still don't know why "Done Work" is "-2.00" and "4.00" in my case although there is much more "Done Work"...?

Also I do not understand this statement in your post:

"The Not Done data is used to draw the Work Remaining line and the Done bars (green)." ... "Not Done data is used to draw the Done bar?

 

My expectation is that the "done work" is displaying the actual hours booked on the corresponding item and the "removed work" is calculated based on subtraction of "remaining work" of the corresponding item. 

Comparing these two bars would provide an overview of how efficient the "progress" is. For example: removed work would be 30 but done work is 40 at this day. This would mean that either the effort estimation was too optimistic (too low) or issues occured during development which was blocking from effectively working on the task/fulfilling the requirement.

 

 This way it would be very useful. Currently that really seems buggy.

Could you please double check that again?

 

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Valeri Hristov
Telerik team
answered on 24 Aug 2015, 12:36 PM
My statement was not very precise - the formula for calculating the Done work (green bars) for a specific date uses both NotDone and Totals:
DoneDelta = Done[date] - Done[date+1], which translates into:
DoneDelta = (Total[date] - NotDone[date]) - (Total[date+1] - NotDone[date+1])

For example, if today in the morning (date) I have had 100 points of work and now (date+1) I have 80, the delta is 20.

Note that the Done and Total values represent the work in 12AM of each day.

We are using similar formula for calculating the Added/Removed work (orange bars):
AddedDelta = Total[date+1] - Total[date]

The problem with Work Remaining is that the reports are based on Status changes and when the developers update Work Remaining we cannot detect the Done work correctly. Here is a small table that shows the changes in a single Work Item and the corresponding report data that is returned by the API:

 Day of Week Monday Tuesday  Wednesday  ... 
 Work Remaining  10 5 0  
 Status In Progress In Progress Done     
 Totals Report 10  5 0  
 Done Report 0 0 0  
 NotDone Report 10 5 0  
 TotalDelta -5 -5 -  
 DoneDelta 0 0 -  

I agree with you about the formula for the Done Delta. However, since we don't have "original work" property, but it is calculated - PERT(Optimistic, Probable, Pessimistic) it might not be obvious what exactly happens. In any case, most probably it will be much better than the current report.

I discussed your proposal with the team and we implemented the change. It will be included in the next official release of TeamPulse.

As a small token of gratitude for your involvement, please accept 5000 Telerik points.

Regards,
Valeri Hristov
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Michael
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answered on 25 Aug 2015, 10:25 AM

Hey Valeri,

great! I am curious and looking forward to check the update.

Thanks for the points ...goold service, appreciated it.

Best regards

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Valeri Hristov
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