Any suggestions for the best way to visualize the data once we have it? Are there some existing LIMN graphs that would be well-suited for a funnel analysis like this one? Or should we simply use a standard line graph as we do for other descriptive metrics studies?

Limn doesn't have many graph types but it might have a decent one for this purpose: http://debugging.wmflabs.org/graphs/ordinal_example

So you could have Step 1, Step 2, Step 3, ... on your X axis, then the number of people who made it through each step on your Y axis.

For a better funnel visualization, we should really support Sankey diagrams: http://www.practicalecommerce.com/files/images/0005/0938/2_goalFlow_Large.png

+1, this might be overkill for a linear funnel with a small number of nodes (where a directed graph visualization, a line chart or an actual “funnel” [1] could do the job). I agree Sankey diagrams would be nice to have down the line for more complex scenarios.

Dario

[1] https://github.com/smilli/d3-funnel-charts

[2] The d3 implementation: http://bost.ocks.org/mike/sankey/