## dinsdag, december 06, 2011

### A Pareto Chart

While I was writing the article about “Control charts”, I found out about “The Seven Basic Tools of Quality”. It was the first time I learned about that – and I realised that at least 4 of those seven tools can be built in Business Objects DeskI and WebI.

Those four tools are :

• A Control chart (described in a previous article)
• A Pareto chart
• A Histogram
• A Scatter Diagram

In this particular article, I wish to show you a Pareto Chart.

Basically, it is a chart that shows a bar and a line, where the line illustrates the importance of each of the bars.

This is accomplished by sorting the values from high to low and presenting them on a bar-chart. And then, adding the RunningSum/Total on a linechart.

The above chart shows that 50% of our reservations are made in 3 months April, August and February.

I realise that this isn’t the typical sort of data on which you use this particular chart, but I do believe this can be a useful way of presenting pretty much any kind of number. Where you want to compare your number to a % in total.

The example used on WikiPedia is various sources of absenteism. In an other source, I found the possible deseases among cattle, in order to find the deseases you want to tackle first.

So, enough talk. Without any further ado: The Pareto Chart.

Step 1. List your data in a table and sort it Large to Small :

Step 2 :

Calculate the Runningsum and divide by the total:

=RunningSum([Future guests])/Sum([Future guests]) in Report * 100

I multiply times 100 to make it a bit cleaner on the z-axis of the chart.

As soon as you do this however, any sorting on the table is gone, so we’ll have to re-sort.

Step 3: Click View structure, sort the measure you want to have sorted:

Second problem, the scale is wrong. It should be from 0 to 100. On the properties tab, make sure you set it to be 0 to 100. Given the type of number we have here, it will never be anything else than 0 to 100.

And we have ourselves a PARETO-chart.

Peter De Rop