Stuff happens (in people's lives and in a society at large) when a number of things aggregate. Very often, we have limited idea of what are all those things, leave aside how much of each ingredient is required and in what sequence, to get the stuff to happen. In other words, we know little about the "stuff-happening" function! And worse still, this function varies across contexts.
I say it in the context of this Times story highlighting a failed attempt to provide healthy-food choices to residents of a poor Bronx neighborhood. Though the New York city government's tax incentive program helped establish a healthy-food supermarket, it had little effect on the diets of neighborhood residents. People continued their earlier unhealthy food consumption. The article also points to latest research, which show that people's preferences, more than access, determine their eating habits.
Our results indicate that policies aimed at improving access to healthy foods in underserved areas will leave most of the socioeconomic disparities in nutritional consumption intact.
A significant number of opinion-makers are likely to take away the message that the US federal government's program to improve healthy food habits by incentivizing grocery stores to locate to places with high obesity rates which they had hitherto avoided, may be money down the drain.
On similar lines, social researchers who swear by evidence-based policy design have found that school buildings and textbooks have limited effect on learning outcomes, whereas deworming or provision of information to parents on returns to education have large effects. They decry the wasteful spending on these items and favor using the scarce resources on the cheaper alternatives like deworming or providing information. And there are several other similar evidence-based inferences.
The researchers would point to the need for such prioritization given the scarce resources available. But they overlook the damage done by the headline grabbing takeways - pare down public support for the program to encourage healthy-food grocery stores to set up shop in disadvantaged areas or scale back funding for providing textbooks or building schools and focus on deworming and providing information. Needless to say, these micro-evidence based inferences fly against more historical macro-evidence.
Just as access is a necessary, but not always sufficient, condition for ensuring healthy eating, no society has ever achieved acceptable learning outcomes across it without having good physical school infrastructure and textbooks for children. Attempts to change the food preferences of poor people are more likely to succeed when they have ready access to places where they can buy such food. Similarly, learning outcomes are more likely to improve when children have textbooks and are taught in a school with reasonable physical infrastructure.
While the process of making stuff happen is generally always iterative, we should not lose sight of the insight that stuff happens when several ingredients, often diffuse and spread over time, come together. Unfortunately, such findings are not amenable to headline grabbing evidence-based research. See also how this research popularized by this article flounders when faced with arguments here.