Disclosure:

  • The charts below are part of completely separate analyses.
  • Identifiable data has been altered and names changed to maintain complete anonymity.
  • As most charts are done using Tableau, they are interactive and best viewed full screen.
  • You can hover over data points, columns, use the filters, whatever you wish, you’re not going to break them.

OUTLIERS

Outliers need to be spotted as early in the analysis as possible. Each company has their own way of dealing with outliers as they can have a large effect on the outcome of analysis. So make sure you get that clarified as early in the process as possible.

Finding outliers can be achieved in many ways, I always tend to throw the standard deviation in many charts just to get a quick feel for things.

Standard Deviation

In the chart below, I’ve plotted:

  • Profit for each order
  • Orders are plotted on the time scale to get a feel if specific periods in the year tend to produce a similar pattern
  • The Red and Blue lines represent the outer limits of the standard deviation
  • In the upper right corner you can slide the standard deviation slider to set the deviation you want to filter for
  • As you hover your cursor over the data points, details related to that point are displayed
  • Of course Blue vs Red dots distinguish between what’s within and outside the boundaries
  • I use standard deviation measures regularly in work related to Six Sigma
  • The outer limits could be standard deviation, or could be any limits you wish to separate for as you’ll see in top/worst performing charts 

Circle Chart

Here once again it’s easy to find the outliers in both Sales and Profit using a simple chart.

  • Feel free to hover over the data points to view details pertaining to each one
  • If you wish to isolate the data points by category look in the upper left corner and click on the specific color label for each category. That will isolate the data points for that category and fades the rest

Simple Bar Chart

Does it get any easier than this to spot an outlier?

Middle Axis Chart

In the next chart which plots the Profitability of each product, it’s easy to filter as well as spot the outliers

  • The dots (data points) are colored based on their profitability Ratio
  • The colors are detailed in the upper right side of the chart
  • You get to set the parameter for what is profitable or not
  • In the upper right box labeled Profitability KPI feel free to enter any percentage in the box (using decimals), for example if you want to set it to 15% type in 0.15 and press enter and the chart will adjust accordingly