SUMMARY
The
Index function in a PivotTable calculates a weighted average by using the following formula:
((value in cell) x (Grand Total)) / ((Grand Row Total) x (Grand Column Total))
When you use PivotTables to compare the relative importance of your row data versus your column data, it can be extremely helpful to
display your data as an Index. For example, this article demonstrates that if you display data in the
Index format instead of a
Percentage of Total format, you can often reveal valuable comparisons that you might not otherwise see.
The first section of this article describes how to create two PivotTables: one that displays sales figures as a
Percentage of Total and another that displays sales figures as an
Index. The second section of this article ("Analysis of the Results") explains the advantages of being able to compare data displayed both ways.
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Create Sample Worksheet and PivotTables
To create the sample worksheet and PivotTables, follow these steps:
- Create a new worksheet and enter the following values:
A1: Fruit B1: State C1: Sales
A2: Bananas B2: CA C2: $800,107
A3: Pears B3: TX C3: $547,236
A4: Kiwi B4: CA C4: $669,076
A5: Apples B5: CA C5: $622,236
A6: Cherries B6: CA C6: $656,097
A7: Pears B7: CA C7: $674,218
A8: Cherries B8: PA C8: $697,711
A9: Kiwi B9: CA C9: $550,637
A10: Bananas B10: PA C10: $602,124
A11: Apples B11: PA C11: $669,916
A12: Kiwi B12: PA C12: $693,306
A13: Apples B13: TX C13: $589,278
A14: Pears B14: PA C14: $739,241
A15: Cherries B15: TX C15: $682,213
A16: Bananas B16: TX C16: $791,944
- To create the first PivotTable, select any cell that contains data, and then click PivotTable and PivotChart Report on the Data menu.
- In the PivotTable Wizard, click Next.
- Confirm that the Range setting is $A$1:$C$16. If it is, click Next. If it is not, drag to select cells A1:C16, and then click Next.
- Click Existing Worksheet. Click cell E1, and then click Finish.
- Drag the button that is labeled Fruit to the box that is labeled Drop Row Fields Here. Drag the button that is labeled State to the box that is labeled Drop Column Fields Here, and drag the button that is labeled Sales to the box that is labeled Drop Data Items Here.
When you are finished, the first PivotTable is in cells E1:I8.
- Right-click in the data field, and then click Field Settings on the shortcut menu.
- In the PivotTable Field dialog box, click Options. In the Show data as list, click % of total, and then click OK.
- To create the second PivotTable, repeat steps 2 through 6.
NOTE: In step 4, when Excel asks whether you want your new report to be based on the same information as your existing report, click No. In step 5, click cell E10 to place the new PivotTable.
When you are finished, the second PivotTable is in cells E10 to I17. - After you create the second PivotTable, right-click in the data field, and then click Field Settings on the shortcut menu.
- In the PivotTable Field dialog box, click Options. In the Show data as list, click Index, and then click OK.
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Analysis of the Results
Example 1
If you compare the sales of bananas in Texas and California, the figures from the first PivotTable (Percentage of Sales data) show that slightly more bananas were sold in California (8.01% in cell F4) than were sold in Texas (7.93% in cell H4).
However, if you look at the second PivotTable (Index data), you can see that bananas are much more important to the Texas market (1.38 in cell H13) than they are to the California market (0.916 in cell F13).
If you examine the tables more closely, you discover that Texas had zero kiwi sales (versus California's 12% kiwi sales), which makes other fruits (including bananas) more important to the overall sales amounts in Texas.
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Example 2
If you compare the sales of bananas in California to the sales of kiwi in Pennsylvania, the figures from the first PivotTable (Percentage of Sales data) show that significantly more bananas were sold in California (8.01% in cell F4) than kiwis in Pennsylvania (6.94% in cell G6).
However, by looking at the second PivotTable (Index data), you can see that kiwis are more important to the Pennsylvania market (1.06 in cell G15) than bananas are to the California market (.916 in cell F13).
In a case like this, it can be difficult to tell why bananas, although a larger dollar amount, are not as big a portion of California's overall sales as kiwis are in Pennsylvania. One explanation could be that Pennsylvania kiwis, a moderately selling item, are high cost, therefore making them more valuable overall.
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