Improved sanitation is an unqualified good (if, as Mtega points out, it really is ‘improved’), but I don’t think we should pretend that CLTS is some participatory revolution – it’s neither brand new nor necessarily all that democratic.

As a friend bluntly puts it, “If the intended outcome [of CLTS] is shitting indoors then great, but let’s not pretend it’s teaching anything else around participation, empowerment, democracy and equality.”

I have seen CLTS in action in Bangladesh and Tanzania, and it can be just as Robert Chambers describes here – thrilling and inspiring. That was what I saw in Bangladesh. But in the wrong context it can be a waste of time and resources.

CLTS works by provoking a powerful sense of shame, first among communities that some of their members don’t have or don’t use latrines, and second in individuals who are defecating openly. People are essentially shamed into building simple latrines.

That works well when open defecation is common, as was the case where I saw CLTS at work in rural Bangladesh, as well as parts of rural Africa and in many urban slum settings.

But in most of Tanzania, the vast majority of households (typically over 95% in most areas) have their own pit latrine – the legacy of a very effective health promotion campaign 40 years ago. Where I saw CLTS mobilisers trying to provoke shame at open defecation in this setting, the only shame present was the community’s embarrassment at the mobilisers’ lack of understanding of the local context.

Tanzania’s challenge is to persuade people to upgrade from very basic latrines, which are often very ineffective barriers against the spread of disease, to something more lasting and effective. Nobody has yet found a way to do this.

CLTS is very effective at getting people in other countries away from open defecation to where Tanzania already is. But it has proved unable to take people a step higher, to persuade people to construct latrines that will prevent the spread of disease.

With some of CLTS’s main advocates not willing to accept any criticisms of the approach, we need to guard against the danger of overlooking its weaknesses and assuming the sanitation problem is solved. Tanzania’s experience shows that getting people away from open defecation, while important, is only a first step, and one that leaves people still at serious risk of diarrhoeal disease.

Finally, I should add that the possibility of CLTS contributing to putting the sanitation MDG back on track is very small. The MDG monitoring for sanitation rightly specifies “improved sanitation”. The full definition of an “improved” latrine is complicated, but for pit latrines it essentially boils down to whether the latrine has a washable slab – i.e. one made of ceramic, plastic or cement.

In my experience the majority of latrines constructed as a result of the CLTS process don’t have washable slabs and are therefore not classed as “improved”, since CLTS leaves households and communities to design their own latrines.

This final point is not strictly a criticism of the CLTS approach, just a clarification that it’s impact on the MDG for sanitation is likely to be very small.