Mon 4 Feb 2013
Causality isn’t the same as explanation: why development needs more of the latter
Posted by Ed under Academia, development, policy, research
[16] Comments
I have a confession. For a long time now I have found myself befuddled by those who claim to have identified the causes behind observed outcomes in social research via the quantitative analysis of (relatively) large datasets (see posts here, here, and here). For a while, I thought I was seeing the all-to-common confusion of correlation and causation…except that a lot of smart, talented people seemed to be confusing correlation with causation. This struck me as unlikely.
Then, the other day in seminar (I was covering for a colleague in our department’s “Contemporary Approaches to Geography” graduate seminar, discussing the long history of environmental determinism within and beyond the discipline), I found myself in a similar discussion related to explanation…and I think I figured out what has been going on. The remote sensing and GIS students in the course, all of whom are extraordinarily well-trained in quantitative methods, got to thinking about how to determine if, in fact, the environment was “causing” a particular behavior*. In the course of this discussion, I realized that what they meant by “cause” was simple (I will now oversimplify): when you can rule out/control for the influence of all other possible factors, you can say that factor X caused event Y to happen. Indeed, this does establish a causal link. So, I finally get what everyone was saying when they said that, via well-constructed regressions, etc., one can establish causality.
So it turns out I was wrong…sort of. You see, I wasn’t really worried about causality…I was worried about explanation. My point was that the information you would get from a quantitative exercise designed to establish causal relationships isn’t enough to support rigorous project and program design. Just because you know that the construction of a borehole in a village caused girl-child school attendance to increase in that village doesn’t mean you know HOW the borehole caused this change in school attendance to happen. If you cannot rigorously explain this relationship, you don’t understand the mechanism by which the borehole caused the change in attendance, and therefore you don’t really understand the relationship. In the “more pure” biophysical sciences**, this isn’t that much of a problem because there are known rules that particles, molecules, compounds, and energy obey, and therefore under controlled conditions one can often infer from the set of possible actors and actions defined by these rules what the causal mechanism is.
But when we study people it is never that simple. The very act of observing people’s behaviors causes shifts in that behavior, making observation at best a partial account of events. Interview data are limited by the willingness of the interviewee to talk, and the appropriateness of the questions being asked – many times I’ve had to return to an interviewee to ask a question that became evident later, and said “why didn’t you tell me this before?” (to which they answer, quite rightly, with something to the effect of “you didn’t ask”). The causes of observed human behavior are staggeringly complex when we get down to the real scales at which decisions are made – the community, household/family, and individual. Decisions may vary by time of the year, or time of day, and by the combination of gender, age, ethnicity, religion, and any other social markers that the group/individual chooses to mobilize at that time. In short, just because we see borehole construction cause increases in girl-child school attendance over and over in several places, or even the same place, doesn’t mean that the explanatory mechanism between the borehole and attendance is the same at all times.
Understanding that X caused Y is lovely, but in development it is only a small fraction of the battle. Without understanding how access to a new borehole resulted in increased girl-child school attendance, we cannot scale up borehole construction in the context of education programming and expect to see the same results. Further, if we do such a scale-up, and don’t get the same results, we won’t have any idea why. So there is causality (X caused Y to happen) and there are causal mechanisms (X caused Y to happen via Z – where Z is likely a complex, locally/temporally specific alignment of factors).
Unfortunately, when I look at much quantitative development research, especially in development economics, I see a lot of causality, but very little work on causal mechanisms that get us to explanation. There is a lot of story time, “that pivot from the quantitative finding to the speculative explanation.” In short, we might be programming development and aid dollars based upon evidence, but much of the time that evidence only gets us part of the way to what we really need to know to really inform program and project design.
This problem is avoidable –it does not represent the limits of our ability to understand the world. There is one obvious way to get at those mechanisms – serious, qualitative fieldwork. We need to be building research and policy teams where ethnographers and other qualitative social scientists learn to respect the methods and findings of their quantitative brethren such that they can target qualitative methods at illuminating the mechanisms driving robust causal relationships. At the same time, the quantitative researchers on these teams will have to accept that they have only partially explained what we need to know when they have established causality through their methods, and that qualitative research can carry their findings into the realm of implementation.
The bad news for everyone…for this to happen, you are going to have to pick your heads up out of your (sub)disciplinary foxholes and start reading across disciplines in your area of interest. Everyone talks a good game about this, but when you read what keeps getting published, it is clear that cross-reading is not happening. Seriously, the number of times I have seen people in one field touting their “new discoveries” about human behavior that are already common conversation in other disciplines is embarrassing…or at least it should be to the authors. But right now there is no shame in this sort of thing, because most folks (including peer reviewers) don’t read outside their disciplines, and therefore have no idea how absurd these claims of discovery really are. As a result, development studies gives away its natural interdisciplinary advantage and returns to the problematic structure of academic knowledge and incentives, which not only enable, but indeed promote narrowly disciplinary reading and writing.
Development donors, I need a favor. I need you to put a little research money on the table to learn about whatever it is you want to learn about. But when you do, I want you to demand it be published in a multidisciplinary development-focused journal. In fact, please start doing this for all of your research-related money. People will still pursue your money, as the shrinking pool of research dollars is driving academia into your arms. Administrators like grant and contract money, and so many academics are now being rewarded for bringing in grants and contracts from non-traditional sources (this is your carrot). Because you hold the carrot, you can draw people in and then use “the stick” inherent in the terms of the grant/contract to demand cross-disciplinary publishing that might start to leverage change in academia. You all hold the purse, so you can call the tune…
*Spoiler alert: you can’t. Well, you probably can if 1) you pin the behavior you want to explain down to something extraordinarily narrow, 2) can limit the environmental effect in question to a single independent biophysical process (good luck with that), and 3) limit your effort to a few people in a single place. But at that point, the whole reason for understanding the environmental determinant of that behavior starts to go out the window, as it would clearly not be generalizable beyond the study. Trust me, geography has been beating its head against this particular wall for a century or more, and we’ve buried the idea. Learn from our mistakes.
**by “more pure” I am thinking about those branches of physics, chemistry, and biology in which lab conditions can control for many factors. As soon as you get into field sciences, or starting asking bigger questions, complexity sets in and things like causality get muddied in the manner I discuss below…just ask an ecologist.
16 Responses to “ Causality isn’t the same as explanation: why development needs more of the latter ”
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Many would have made the opposite argument about development econ 10 years ago–that there is too much thinking about mechanisms, and not enough testing of causality. Think about the famous papers of the 1990′s. We had Banerjee Newman on occupational choice, we had the endogenous growth literature, and a bunch of growth regressions. The Duflo field experiment revolution made development econ about atheoretical local average treatment effects. The development wind has recently started to blow in the other direction again.
David:
Perhaps…except that even in that period of development economics, what I never saw was the sort of qualitative work that is necessary to really tease out the mechanism/process behind the causal relationship. I think that “story time” explanation has been something of a constant when it comes to the shift from identification to explanation.
And the RCT stuff is odd – some of it is, as you say, theoretical. But a lot of it starts from an economic claim about behavior from the literature and then seeks to test that theory, so it is in fact quite theoretical. Whether or not the theories being tested make any sense, or whether they really require testing, is a separate manner.
Yes, I think the winds are blowing back in academia…but how to translate this into policy and practice? Simply put, the more qualitative understandings of the world tend to be plural, of middling confidence, and they take a while to build. This probably represents the world as it is quite accurately…but it makes policy types who want simple narratives crazy. To be honest, I feel like the RCT allowed a certain brand of economics to (re)colonize development studies as the gold standard of knowledge (doing a quick article on this now), and it could be a long time before we can dig out of that hole…
Thanks for an interesting start to my morning! Have you
seen Causality for Beginners by Ray Pawson?
http://eprints.ncrm.ac.uk/245/ It sets out the difference between
the ‘X leads to Y’ and the ‘how did X lead to Y’ approaches very
nicely.
Allow me to test my own formulation of the/a challenge. My
impression is that it’s along a similar line of reasoning. Because
‘development’ is complex, non-linear and multifactorial, averages
or descriptions of point (a) and then point (b) isn’t really useful
information on their own, if it’s ‘changing the world’ we’re after.
What we need to describe and understand are the individual
trajectories – which happens to be the blind-spot of most
quantitative research. I’ll give a very cross-disciplinary book
suggestion: Nobel laureate and physical chemist, Ilya Prigogine’s
“The End of Certainty: Time, Chaos, and the New Laws of Science”
1997 (Very fascinating read, although I’ll have to admit I didn’t
read all chapters.)
Ps. It might also be Alexander Bogdanov, since I can’t find the quote now, but I think it is Prigogine who says something like: If we in the process of finding an answer to a stated problem, isolate the problem to the extent that it is removed from the context from which it arose in the first place; The answer is likely to be worthless.
Ed, I agree with you. Qualitative fieldwork with cross disciplinary research and conversations. Also, academics being willing to give up a little space on their own podium to give space and credence to others. I suspect that often (I say suspect but I’m just being British and polite) when inter disciplinary discussions are held, most people aren’t listening properly – they are holding their collective breaths and waiting until it’s their turn to pontificate. If we don’t listen to one another, all the intelligence and research in the world won’t help. It’s a waste.
Cecile:
Yes, I fear you are correct – academia breeds the need to tell everyone what you are doing/can do, but does little to teach us to listen to others…especially others from different disciplinary/epistemological perspectives. I agree that this is a waste…one that I would like to see less of over time. I think that is why I am keen to take advantage of the funding crisis in higher education to push people into conversations they might not otherwise have. We need to incentivize listening and making space for others, and within the structure of academia the lowest-hanging fruit is research dollars…
Thank you thank you thank you! I hope you continue to push on this issue.
Have you read Levy-Paluck’s piece on the ‘promising integration’ of qualitative work into field research? She separates out treatment effects and treatment mechanisms in a potentially helpful way.
I think continuing to better articulate how mixed-methods work can be put into practice in a way that enhances the value of all the methods mixed-in will be an important step forward.
I hope the donors are listening and that the development journals are ready! I think more folks (like 3ie) are looking at mixed-methods work but with less idea about what to do with all that additional data.
Thank you! I am working on this pretty continuously…my life is projects that cannot be answered by applying only one method, and the teams I work with are mostly quantitative, so I am building a lot of practical experience at this intersection. I have not seen the Levy-Paluck piece you reference – I can dig around, but do share the citation! Anything that helps me better think about and articulate what I am doing vis a vis methods is useful. I will say that I have had no real problem getting qual work into journals, so mixed work shouldn’t be a big problem – and I am currently working on mixed-methods stuff for USAID and the World Bank, so at least the people I work with at those donors are eager to see what we can do!
Great! The Levy-Paluck piece is “The Promising Integration of Qualitative Methods and Field Experiments” in “The ANNALS of the American Academy of Political and Social Science 2010 628: 59. It’s focused most specifically on impact evaluations. I’d be keen to hear what you think.
Nice to hear that someone is forging a career at the methods-intersection. I’d be interested to hear more about your present work!
Causal attribution and causal explanation is a useful distinction to make, for reasons you give above. So is the distinction between useful predictions (enabled by stats analysis) and useful explanations (e.g. enabled by case studies). Please excuse this quote from my own recent paper at http://mande.co.uk/blog/wp-content/uploads/2013/01/Decision-Trees-and-ToCs-Vs-20121227-NPW1-1.docx
“Valid explanations of causal processes behind the associations found in a configuration may not always be needed. Decision Trees and other methods (e.g. artificial neural networks), may generate accurate predictions which are useful in themselves, without any knowledge of the underlying causal processes. These are known as “black box” models. Accurate predictions of public behaviour in response to immunisation campaigns and to the provision of other government services could make a substantial difference to the design of such services and thus their subsequent uptake. Not surprisingly, there is significant on-going research on the use of Decision Trees to predict stock market behaviour . Those involved are not seeking to understand and subsequently influence stock market behaviour, just to profit from its behaviour as it emerges. On the other hand valid explanations are useful when activities are being designed with the intention of producing the desired outcome. For example, changing people’s health seeking behaviour.”
Thanks for the thoughtful post. I am not as familiar with social science and economic research as I am with epidemiology. But as I was reading this I wonder if there is any analogy within the economics thinking on causality to the Bradford-Hill criteria used by epidemiologists to assess whether claims of causality are plausible. If there isn’t an equivalent there should be! Here are the criteria:
1. Strength of association (relative risk, odds ratio)
2. Consistency
3. Specificity
4. Temporal relationship (temporality) – not heuristic; factually necessary for cause to precede consequence
5. Biological gradient (dose-response relationship)
6. Plausibility (biological plausibility)
7. Coherence
8. Experiment (reversibility)
9. Analogy (consideration of alternate explanations)
Wiki: http://en.wikipedia.org/wiki/Bradford_Hill_criteria
Brilliant! I particularly love this part: “My point was that the information you would get from a quantitative exercise designed to establish causal relationships isn’t enough to support rigorous project and program design. Just because you know that the construction of a borehole in a village caused girl-child school attendance to increase in that village doesn’t mean you know HOW the borehole caused this change in school attendance to happen. If you cannot rigorously explain this relationship, you don’t understand the mechanism by which the borehole caused the change in attendance, and therefore you don’t really understand the relationship.”
I may quote you!