13 February 2013

Does slum upgrading work?

A new colleague at OPM Ruhi Saith is a co-author of a new Cochrane systematic review on the impact of slum upgrading programmes on health and wellbeing (full summary here).

They find only 5 studies which can demonstrate any causality, from which they find:
  • "Limited but consistent evidence to suggest that slum upgrading may reduce diarrhoea in slum dwellers and that slum dweller’s water related expenses may also be reduced
  • Mixed results for whether slum upgrading can reduce parasitic infections, educational outcomes, financial poverty and unemployment outcomes
  • Very little information on other health or social outcomes, or which types of interventions were most beneficial"
Which reminds me of two things,

first, John Snow and the 1854 Broad Street cholera epidemic, when John used a mixed methods approach based on KII*, and a pathbreaking geographic data visualization infographic** which founded the science of epidemiology using one of the first natural experiments.

second, that there is really weak evidence that area-based initiatives have any impact on employment and well-being in the UK, and so policy should target people not places

Which suggests that slum upgrading should focus on providing the public goods and infrastructure with clear evidence of impact and cost effectiveness - namely clean water and sanitation - and be more modest about expectations for impacts on other outcomes which are not primarily determined by the slum environment, such as poverty, unemployment, and low education.

*Key informant interviews. Or talking to people. Yes I am mocking your terminology, quals.
**A map. Yes you too, data monkeys.


Matthew Collin said...

1) I'm surprised there's enough evidence here for a systematic review - a scan over the studies included reveal multiple contexts and different types of interventions, much of it of dubious causal validity. Also note that most slum upgrading is of fairly poor quality (I've watched the same road in Dar es Salaam be half-built, destroyed, built, destroyed, then finally built again, after 4 years).

2). I'm bothered by your narrow focus on what has already shown to be cost-effective in helping people. Slum-upgrading isn't just about public health or individual welfare, it's about house prices, the growth of cities/informal settlements, politics, and land tenure. I agree that we should keep in mind what has the most evident and immediate welfare gains, but I don't think you can really sweep the other stuff under the rug.

rovingbandit said...

I was also making some inference based on a bit of wild leap from research in very different contexts which shows that improving the physical environment either doesn't work or is very cost ineffective in improving employment or incomes. Move people out of the ghetto and their outcomes hardly improve. Improve the ghetto, and house prices rise pushing the poorest somewhere else and replacing them with some better off people from elsewhere. I just think its a bit strange to look for employment and income outcomes from physical environment interventions, and you are much better off targeting people rather than the places that they live.

I'd agree that politics and land tenure could be important for employment and income, but that's not what I would normally think of when someone says slum upgrading, but I might just be wrong there.

Matthew Collin said...

I think we're misunderstanding each other to an extent. I agree completely that we should have a focus on people - full stop. That said, improving the physical environment is often going to have effects which are A) going to be hard to measure on an individual level because people move around and there are tons of externalities, but B) are still *extremely important* because they effect how slums grow, where people move, and what the next neighbourhood is going to look at. These are all things which are going to be hard to pick up in a standard impact evaluation, hence my concern that if we take a narrow "let's only focus on what we can prove in the realm of health and job creation", we could very easily get stuck in a track where we're playing whack-a-mole with social policies, but not focusing on the underlying infrastructure/systems which are generating these outcomes.

And two more thoughts:
*In the (admittedly ideal) situation where the poor are the ones owning the land, if land prices push them somewhere else, this is only going to be a pareto improvement, no?

*Land tenure is mentioned as one of the composite parts of slum upgrading in the review you cite above, and it's usually thought of part of "the package" in most studies I've read.

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