Plot second series on SSRS line chart

I am creating a chart for reading measurements in elementary schools.
Please see the attachment.
The red line in the attachment does not exist on my chart.  I drew it in with an editing program.
I would like to plot this secondary line from the student's first reading measurement for the year to the the end of the year goal, thus showing adequte progress for plots above and below the goal line.
Any ideas/assistance would be most appreciated.
ReadingChart.jpg
JEClark1Asked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Tim HumphriesDirectorCommented:
Hi,

You might find this post useful:

http://blogs.msdn.com/b/robertbruckner/archive/2008/11/09/trendlines-calculated-series-in-reporting-services-charts.aspx

Not sure if you c an extrapolate the line beyond your data series, though.

Tim
0
JEClark1Author Commented:
Tim
Thanks for the reply.  Two problems are extrapolating and that I don't need a calculated arithmetc function, but instead need a straight line from the student start point to the spring end goal.  Thanks again.
0
Tim HumphriesDirectorCommented:
Hi,

Ok, I think you need to create a second dataset  that provides fields to enable you to create a linear regression curve.

I followed the formulae in this link: http://people.hofstra.edu/stefan_waner/realworld/calctopic1/regression.html

I created a second dataset based on the first that simply returns the values to plug into the formulae. Key to this working well is getting your month as an ordinal, so the first month in your range maps to '1', the second to '2' etc.)

You then need a query that returns the following:

Sum(wcpm) SumX, Sum(monthAsOrdinal) SumY, Sum(wcpm * monthAsOrdinal) SumXY,
Sum(wcpm * wcpm) SumX2, Count(*) NumValues

which groups over your entire set of values.

You can then add a second table to your report that uses the new dataset (above any existing tables and your chart so it is evaluated first) and add the following expressions in two cells:

=Code.SetM((Fields!NumRows.Value * Fields!SumXY.Value - Fields!SumX.Value * Fields!SumY.Value) / ((Fields!NumRows.Value * Fields!SumX2.Value) - Fields!SumX2.Value))

and

=Code.SetB((Fields!SumY.Value - Code.GetM() * Fields!SumX.Value) / Fields!NumRows.Value)

Then in the Report Properties / Code section add the following:

private shared m as double
private shared b as double

Public Function SetM(value as double) as double
    m = value
return m
End Function

Public Function GetM as double
  return m
End Function

Public Function SetB(value as double) as double
  b = value
  Return b
End Function

Public Function GetB As double
  Return b
End Function


This code enables you to store the values for M and B (gradient and intercept) for use in a new calculated series in your chart.

Your main dataset, which returns your month and wcpm values also needs to return the monthAsOrdinal value. You can then calculate the position on your straight line as

=Code.GetM() * Fields!monthAsOrdinal.value + Code.GetB()

This will then show an extra straight line correlation on your chart.

Tim
0
JEClark1Author Commented:
Tim
Thanks for the detailedresponse.  I will have to try it to see the results.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
JEClark1Author Commented:
Well thought out repsonse.  Thank you!
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Microsoft SQL Server 2008

From novice to tech pro — start learning today.