Feedback on my first Data Viz blog led me down the conversion funnel
My first blog and in class presentation used Tableau to explore conversion rates
My feedback suggested funnel charts and Sankey diagrams, and a free app rawgraph.io site.
A Sankey Diagram, and the more recent Alluvial Charts are an attention grabbing flow diagram
These diagram types basically map the change between a number of histograms showing the same data, but split different ways, as shown by the example alluvial diagram created by Cory Brunson in Diagram 1.
Diagram 1 An Alluvial Diagram using the Titanic data set http://corybrunson.github.io/ggalluvial/articles/ggalluvial.html
Data cleaning was an iterative and educational process
Once I began experimenting with the tool, I questioned my decision to use Alluvial charts almost immediately!
The data I had was conversion data but was not at all in the right format, basically columns of the data by day.
Thankfully the rawgraph tool was fast, so I could play with the data.
The original data ended up like Table 2 below. It was completely aggregated without any of the daily detail.
Table 2 Final data format
For the 55,361 attempted logins, I ensured the categorical variables all added to this number by creating new variables.
The Source variable I defined as the original Mobile, Desktop and Tablet, but then added in Login, Redemption and Sign Up.
For the Destination variable I created the Login, Redemption, Sign up and Cancel Login, Cancel Redemption and Cancel Sign up values.
Lastly for the device variable, I had the original mobile, desktop and tablet and then created a Lost variable.
rawgraph was super easy to use
rawgraph was an excellent tool for quickly learning about the graphs and what data is required for them.
The website has a comprehensive library of guides.
I used “How to make an alluvial diagram” https://rawgraphs.io/learning/how-to-make-an-alluvial-diagram/
There are four steps:
- Load your data
- Choose the layout
- Map your dimensions
It was iterative: cycling through steps 1- 4 and reformatting the data based on what I learned, but luckily the site was very responsive.
Step 1 Load your data
I actually just pasted mine in, easy!
Figure 1 Step 1
Step 2 Choose a Chart
rawgraphs has 21 chart templates and the ability to create a custom chart.
Figure 2 Step 2
Step 3 Map your dimensions
As shown in Figure 3, the dimensions on the left are parsed into types (number and strings) to create your graph.
Figure 3 Step 3
Step 4 The final step, customise your Visualisation
In the final step, there are a limited number of customisation options, but not enough!
Figure 4 Step 4
I played around with the order of the Steps, in order to make the chart more meaningful, and ended up with Figure 5 below.
Figure 5 The Final Alluvial Chart
My alluvial chart explains how the traffic moves from mobile desktop and tablet (bottom left column), into the different steps in the funnel (middle column). The right column shows what proportion of this traffic is lost.
Honestly, this does not make intuitive sense to me, so there must be more work to be done in order to have more columns and splits.
Essentially these types of diagrams best represent a snap shot of a segmented population. Working through this type of chart (Sankey, Alluvial and Parallel coordinates) made me realise the shortcomings in the data for this purpose.
If each error landing page had been tagged, then I would have not required a LOST category. So this data was not ideal for use with this type of chart, but I learned a lot!
I guess these charts are useful for temporal comparisons, or have no idea which parts of the website get used most.
In conclusion, I think the rawgraph.io site is easy to use, and great to learn about different charts, and what they can and cannot do, and what data formats they need. But the Sankey-like charts did not work for the data I had, and I needed to do a lot more re-work to get it making sense.
Read on if you want more information on Sankey and Alluvial diagrams
“Sankey Diagrams are attention grabbing flowcharts that help in quick visualisation of the distribution and losses of material and energy in a process. The width of the lines used in drawing the flowchart is proportional to the quantum of material or energy.”
As material or volume flows from one step to the next, all volume must be accounted for, including wastage, new inputs and growth via processing.
“Alluvial diagrams are a type of flow diagram originally developed to represent changes in network structure over time. In allusion to both their visual appearance and their emphasis on flow, alluvial diagrams are named after alluvial fans that are naturally formed by the soil deposited from streaming water.” https://en.wikipedia.org/wiki/Alluvial_diagram
Cory Brunson also had some definitions..
- An axis is a dimension (variable) along which the data are vertically grouped at a fixed horizontal position. The diagram above uses three categorical axes:
- The groups at each axis are depicted as opaque blocks called strata. For example, the
Classaxis contains four strata:
- Horizontal (x-) splines called alluvia span the width of the diagram. In this diagram, each alluvium corresponds to a fixed value of each axis variable, indicated by its vertical position at the axis, as well as of the
Survivedvariable, indicated by its fill color.
- The segments of the alluvia between pairs of adjacent axes are flows.
- The alluvia intersect the strata at lodes. The lodes are not visualized in the above diagram, but they can be inferred as filled rectangles extending the flows through the strata at each end of the diagram or connecting the flows on either side of the center stratum.”