Misleading charts and data

[Expiry]

Why would you ALWAYS refuse to use a pie chart? If you're wanting to show a simple split of resources or something, surely a pie chart is an easy way to show that?

If 10% of my time is spent on admin, 30% on meetings and the rest on sales, for example, a pie chart would work and wouldn't mislead at all.

 

[Jon von der Heyden]

Why would you ALWAYS refuse to use a pie chart? If you're wanting to show a simple split of resources or something, surely a pie chart is an easy way to show that?

If 10% of my time is spent on admin, 30% on meetings and the rest on sales, for example, a pie chart would work and wouldn't mislead at all.

I don't think that Denis meant that they are misleading (although they can be - see link below), rather just that they are pointless.

Personally I prefer a vertical scale 0% - 100%. Which means I would probably use a stacked column.

In fact rather, for me anything suitably represented on a pie is just as easy to represent on a simple table. Anything more than 4 - 5 slices becomes difficult to interpret (imo). I especially hate 3D pie charts: http://www.mrexcel.com/tip142.shtml

 

[Expiry]

I agree that 3D pie charts are rubbish charts.

In fact, someone should do a 3D pie chart to show what percentage of chart types are ok and what percentage are rubbish.

 

[SydneyGeek]

Why would you ALWAYS refuse to use a pie chart? If you're wanting to show a simple split of resources or something, surely a pie chart is an easy way to show that?

If 10% of my time is spent on admin, 30% on meetings and the rest on sales, for example, a pie chart would work and wouldn't mislead at all.

As Jon said, it's not that they are always misleading. They just can't represent large datasets well. Most of the charting I do requires trend information with many data points and I have seen people try to use pies for that. Straight percentages, 3 or 4 points, no problem. but IMO, it's one of the most badly used chart types so I just avoid them on principle.

Denis

 

[hatman]

As Jon said, it's not that they are always misleading. They just can't represent large datasets well. Most of the charting I do requires trend information with many data points and I have seen people try to use pies for that. Straight percentages, 3 or 4 points, no problem. but IMO, it's one of the most badly used chart types so I just avoid them on principle.

Denis

Another chart type that I have seen abused is ye olde bar chart. I've seen people try to plot several years worth of monthly data for several datasets (picture 5 or 6 colored bar sets), and then orient their x-axis vertically so the labels don't overlap, thus making the actual plot area very short and wide, so the trend (if there is one) is even more difficult to see. I don't know why people are so afraid of x-y scatter plots in these cases...

 

[SydneyGeek]

Another chart type that I have seen abused is ye olde bar chart. I've seen people try to plot several years worth of monthly data for several datasets (picture 5 or 6 colored bar sets), and then orient their x-axis vertically so the labels don't overlap, thus making the actual plot area very short and wide, so the trend (if there is one) is even more difficult to see. I don't know why people are so afraid of x-y scatter plots in these cases...

Yep. And can anyone tell me why X-Y Scatter is the only Excel chart type with a numerical X-axis?

Denis