The plot below shows data on participants per year of lengthy series conducted by five law firms. A facet plot, it gives the data in a separate pane for each firm (alphabetically from Carlton Fields to White & Case). Within each pane the left axis varies for the number of participants in the survey year. For example, DLA Piper top right ranges from below 100 participants to around 300 whereas Davies Ward to its left ranges from 500 to 1,200 participants. White & Case’s survey data is missing participants for 2013 and 2014 so the line breaks. This group covers nine in the series at the maximum and six years at the minimum.
Generally speaking, the upward slope of the lines confirms that series gain participants as they continue over the years. The exception was Davies Ward, which declined from the initial burst of enthusiasm in 2005 but then began a recovery until the firm ceased sponsoring the series after 2011.
If a few more series of at least six years duration had full information on participants, we could more confidently assert that brand recognition and appreciation for a series build over time. Certainly this initial view suggests that to be the case.