thinking through funnels of attrition

when first introduced to the idea of a funnel of attrition (my early attempt at a slightly more nuanced and symetric — but still generic — version is here), i largely thought of it as a useful heuristic for thinking about sample size calculations, by being forced to think about issues of awareness and take-up as well as a few steps along a causal chain between initial participation or use and longer terms outcomes of interest.


more recently (including here), i  have tried to use it as a tool for thinking about articulating assumptions in a theory of change about where people might ‘fall out of’ (or never join) an intervention, thus leaving the funnelmore specifically, i tried (along with colleagues) using it as a goal for a conversation with implementing partners (that is, “let’s map out the funnel of attrition”), tackling the question from multiple perspectives. (various perspectives were brought in using personae, which i created beforehand relying partially on average results from the baseline as well as some stylizing to try to bring certain features into the conversation. at first i feared being overstylized but, in the end, i think i had too little detail. i reviewed my notes from the inmates are running the asylum and was reminded of the importance of specificity, even at the expense of accuracy.)


i liked this idea for guiding a conversation because the funnel of attrition is a little more straightforward than a full theory of change but, in constructing it, you still end up articulating some central assumptions, which can be added to thinking about change may/not happen. it seems like a handy building block in a well-considered theory of change.


the intervention in question is a multi-year engagement, with escalating levels of commitment required and difficulty of requirements. it initially struck me that given all the different program elements, it would be relatively easy to discuss about some of the different points at which it could become difficult to continue to stay engaged. this turned out not to be true. i played devil’s advocate far more than i had initially planned, effectively interviewing the personae with pretty specific questions that ended up reflecting my own thinking about the difficulties of sustained engagement more than revealing so many new ideas. this doesn’t mean the exercise was useless in getting others to think through these issues but i had certainly imagined it going a little differently.


my revised thinking is that it may help to have an early draft of funnel of attrition to guide the conversation, even if (or hoping that) this gets trashed and remade in the discussion process — it just helps to have something tangible. this draws on an interesting suggestion from steve montague of even building in a few ‘errors’ into an early draft understanding of a theory of change to present to implementers to help provoke discussionmy working plan for the future engagements i’ll do with the same implementing team is to walk through this draft funnel of attrition from multiple, quotidian perspectives, with specific thought about factors that might facilitate, reinforce, or hinder progression down the funnel (meaning, staying with the program and realizing the intended changes)


this need for tangibility is how i have found myself struggling — somewhat to my surprise — to put together a draft funnel of attrition. one of the key issues is whether each step is necessary to move to the next; this issue is nicely dealt with in rick davies’s effort at a different diagram of attrition. this gets around the problem of whether, say, changes in attitude are required to precede changes in behavior.


but it doesn’t fully get around the challenges of a multi-year, multi-phase program and how to represent this. as noted, different stages of the program present different challenges and so it seems difficult to sum this all up as a ‘maintenance of participation.‘ this glossing over three years of maintaining participation also seems undesirable from the point of view of facilitating the articulation of reasons for dropping out along the way. things also get muddled as to whether to put outputs and outcomes between different phases of the program. again, one issue is necessity and sufficiency and can therefore be addressed as per davies’s suggestion of layered circles. another issue is that it is getting to be just a really long funnel, which is more overwhelming to look at but also a more nuanced guide to conversation and thinking.


we’ll see what comes out!

*addendum from 2 march 2016: the approach of considering enablers and ‘blockers’ at each step of the funnel attrition went pretty well, even though the funnel we used focused almost entirely on the programmatic phases and activities involved in maintaining/using the program over the course of three years. this means for this particular activity, we didn’t really discuss how activities are expected to translate into a series of outputs and outcomes but it still provided fodder for about two hours of discussion. one small thing that would have made the exercise easier would be adding numbers to the spaces between the ‘rungs’ of the funnel so that it was easier to have people in the same spot.

Published by hlanthorn

ORCID ID: 0000-0002-1899-4790

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