In mid May, Anup47 asked a question in the Chandoo.org forums about the use of a VBA macro to run a number of iterations of a variable against two sets of X values, you can see the post here. It turns out that the number of iterations was 500 columns of data with each column having 27 values.
On examination of the problem, it was going to be a straight forward matter of setting up a statistical function Linest and then using the Data Table command to run each set of data through the function.
The Linest will take the input data and return the statistics that Anup wanted.
The Data Table function will feed in the source data and tabulate the Input and Output data.
This Post follows through a worked example which you can follow along, download the Sample file to suit Sample File 97/2003 or Sample File 2007/10 version. The Sample File contains a worked example of the completed model as well as a Practice Page of the original data. Download the Excel 95/2003 or 2007/10 version above.
Please note that the sample file only contains 14 sets of data as opposed to the 500 Anup47 wanted to process.
Setup
There are a few things that needed setting up before the work starts.
- Headers
- Linest Area
- Link Area
- Data Table Area
Once these areas are setup we simply use the Excel Data Table function.
Once the Data Table function has run, the results can be processed or analysed as required.
Headers
The original data was just that, a tabulation of raw data. The two X sets of Data were in Columns 1 & 2. Each Column from D onwards has a set of Y data that was to be processed.
The first thing that was required was some Headers for the Input Data.
This isn’t strictly required but it is good practice and makes it easier to tabulate and analyse results later.
Insert a Row above the first line
Put X1, X2 in A1, B1 and Y1 in D1 and then drag the lower right Black Handle across top to the right and Excel will autofill the remaining cells.
Linest Area
To get the statistics which Anup wanted we will use the Excel Linest function.
Linest is a Statistical Function that takes a set of data and compares it, in this case to two sets of X Values and produces a set of statistical measure relevant to the correlation between the data sets.
This post isn’t going to explain the intricacies of Linest and I refer you to the Links section at the end where you can read more about the Linest function at your leisure.
For our purposes we need to know that Linest is an Array Formula and requires a 5 Row x 5 Column area to be entered into. For now we will just Array Enter the function =Linest($D$2:$D$28,A2:B28,True, True) into B32:F36.
To do that select the range B32:F36, Press F2 and type/paste the equation in, then Array Enter with Ctrl Shift Enter.
Link Area
To Link the Linest equation to a Data Table we need a link cell, which we will put just above the Linest area.
For now just enter a 1 in it.
We can now go back to the Linest area and link the Linest equation to our link area using the equation, =LINEST(OFFSET($C$2:$C$28,,$B$30),A2:B28,TRUE, TRUE)
To do that select the range B32:F36, Press F2 and type/paste the equation in, then Array Enter with Ctrl Shift Enter.
What this does is allow the Linest formula to access different columns Y1 to Y500 depending on the value of the Link cell B30 which is now 1.
Data Table Area
To setup a Data Table area we need a column of Inputs which will be the Run Numbers and the Row Inputs will be links to the Input and Output Cells.
In a range J33:J46 put the values 1 to 14. These will be the Run Numbers. ie Run No 1, Run No 2 etc (Green in the example below).
Across the top of the Data Table area we can put a number of links and associated labels (Yellow and Blue)
In this case there are 4 Output links =B31, =C31, =B34 and =B33 and their associated labels above them, as well as 2 Input equations and there Labels. The Input equations are simple Offset function that retrieves a value from Rows 1 or 2 based on the value of the Link Cell B30.
These are technically not required but make data analysis and identification of individual results later on a lot simpler.
Run Data Table
We can now run the data Table by selecting the Data Table area: J32:P46
Noting that we will be using a Column Input cell and that it will link to $B$30, the Link cell for the Linest command.
What this does is takes the first value from the Column J32:J46 and puts it into B30, then the Linest command will be calculated and the results put into the Data Table area along with the Inputs.
This is repeated for each cell in J32:J46 automatically.
The final Data Table is now populated as below:
You can see by extending the Data Table input column from 14 to 500 that the full 500 columns of Input Data could easily be processed.
Results
You now have a set-off data that can be analyzed using normal statistics, Min, Max, Std Deviation etc, or can be fed into a Pivot Table/Chart for analysis etc.
References
Linest References
http://chandoo.org/wp/2011/01/26/trendlines-and-forecasting-in-excel-part-2/
http://newtonexcelbach.wordpress.com/2011/01/19/using-linest-for-non-linear-curve-fitting/
Data Table References
http://chandoo.org/wp/2010/05/06/data-tables-monte-carlo-simulations-in-excel-a-comprehensive-guide/
How can the Data Table command help you become a data processing super hero?
How can the Data Table command help you become a data processing super hero?
Let us know in the comments below:
13 Responses to “Using pivot tables to find out non performing customers”
To avoid the helper column and the macro, I would transpose the data into the format shown above (Name, Year, Sales). Now I can show more than one year, I can summarize - I can do many more things with it. ASAP Utilities (http://www.asap-utilities.com) has a new experimental feature that can easily transpose the table into the correct format. Much easier in my opinion.
David
Of course with alternative data structure, we can easily setup a slicer based solution so that everything works like clockwork with even less work.
David, I was just about to post the same!
In Contextures site, I remember there's a post on how to do that. Clearly, the way data is layed out on the very beginning is critical to get the best results, and even you may thinkg the original layout is the best way, it is clearly not. And that kind of mistakes are the ones I love ! because it teaches and trains you to avoid them, and how to think on the data structure the next time.
Eventually, you get to that place when you "see" the structure on the moment the client tells you the request, and then, you realized you had an ephiphany, that glorious moment when data is no longer a mistery to you!!!
Rgds,
Chandoo,
If the goal is to see the list of customers who have not business from yearX, I would change the helper column formula to :
=IF(selYear="all",sum(C4:M4),sum(offset(C4:M4,,selyear-2002,1,columns(C4:M4)-selyear+2002)))This formula will sum the sales from Selected Year to 2012.
JMarc
If you are already using a helper column and the combox box runs a macro after it changes, why not just adjust the macro and filter the source data?
Regards
I gotta say, it seems like you are giving 10 answers to 10 questions when your client REALLY wants to know is: "What is the last year "this" customer row had a non-zero Sales QTY?... You're missing the forest for the trees...
Change the helper column to:
=IFERROR(INDEX(tblSales[[#Headers],[Customer name]:[Sales 2012]],0,MATCH(9.99999999999999E+307,tblSales[[#This Row],[Customer name]:[Sales 2012]],1)),"NO SALES")
And yes, since I'm matching off of them for value, I would change the headers to straight "2002" instead of "Sales 2002" but you sort the table on the helper column and then and there you can answer all of your questions.
Hi thanks for this. Just can't figure out how you get the combo box to control the pivot table. Can you please advise?
Cheers
@Kevin.. You are welcome. To insert a combo box, go to Developer ribbon > Insert > form controls > combo box.
For more on various form controls and how to use them, please read this: http://chandoo.org/wp/2011/03/30/form-controls/
Thanks Chandoo. But I know how to insert a combobox, I was more referring to how does in control the year in the pivot table? Or is this obvious? I note that if I select the Selected Year from the PivotTable Field List it says "the field has no itens" whereas this would normally allow you to change the year??
Thanks again
worked it out thanks...
when =data!Q2 changes it changes the value in column N:N and then when you do a refreshall the pivottable vlaues get updated
Still not sure why PivotTable Field List says “the field has no itens"?? I created my own pivot table and could not repeat that.
Hi, I put the sales data in range(F5:P19) and added a column D with the title 'Last sales in year'. After that, in column D for each customer, the simple formula
=2000+MATCH(1000000,E5:P5)
will provide the last year in which that particular customer had any sales, which can than easily be managed by autofilter.
Somewhat longer but perhaps a bit more solid (with the column titles in row 4):
=RIGHT(INDEX($F$4:$P$19,1,MATCH(1000000,F5:P5)),4)
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