Tag: Outliers

It took me time to understand the requirement and figure out the way to design the visualisation. lookup() & windows functions did help a lot to build this requirement

Let me share the steps required to create this visualisation post data is imported into Tableau:

Step 1: Create 2 parameters for the requirement

Select a Middle line: This parameter to provide drop down option for either median or mean

Select A Test: This parameter to select the type of test we want to perform (outliers, Trend or change)

Step 2: Create the calculated fields required for the visualisation

Middle Line: This field is based on parameter “SELECT A MIDDLE LINE” and based on selection we will have either median or mean of sales

 

+3SD: This field is to calculate + 3 standard deviation based on middle line

-3SD: This field is to calculate – 3 standard deviation based on middle line

TEST – Outliers: Boolean field to highlight the outliers in the dataset i.e. if the sales value is either above +3SD or -3SD

 

TEST – TREND: Boolean field to highlight the trend whether current sales > previous month > previous to previous month or current sales < previous month < previous to previous month.

TEST – CHANGE: Boolean field to highlight whether 3 consecutive fields are below or above middle line.

TEST – SELECTION: This field is based on “SELECT A TEST” Parameter and uses above 3 calculated field to show the required value.

Tooltip – Signal: Tooltip to show signal if the sales value matches with any of the parameter selection criteria

Show Text: This is the field to show the necessary text based on parameter selection

STEP 3: There are 3-4 more fields which we need to create but lets start creating data visualisation for first 2 sheets

Drag Order date to column shelf (convert to month)

Drag Sum(sales) and TEST Selection to rows shelf then change it to dual axis followed by sync axis

Drag Middle line, +3SD, -3SD to details in Marks Area

Add a 3 reference lines on the basis of Middle line, +3SD and -3SD

Add Parameter control for Parameters “Select a Middle line” and “Select A TEST”

Then format the sheet as per requirement with tooltips and it will look like following:

Create an new sheet for Text data and drag Show text field to Text

Step 4: Final sheet for Monthly strip chart

For Strip chart, we will need to add following fields into the dataset

TREND: This is boolean field which we will use to highlight the pattern for Trend

CHANGE:This is boolean field which we will use to highlight the pattern for Change

SymbolCOLOR: Based on Parameter selected for the test, this is will return values for the test select and we will use this as also to segregate data into 3 color bucket of blue, amber and orange to show following:

• Meets the test criteria
• Part of test pattern

Finally, we will create 3rd sheet with strip chart:

Drag Order date to column shelf (convert to month)

Then Drag symbolColor to color and shape area under Marks area then create the tooltip to show the values

Step 5: Create the Dashboard

Add all 3 sheets into dashboard as per below image:

Now we are ready with visualization with user experience which we wanted to show.

Click here for Tableau file

Thanks Ann Jackson for this workout.