Monday, February 06, 2012

A Lesson in Policy Evaluation: Moving to Opportunity

“Moving to Opportunity” (MTO) is a very fine example of a well thought-out evaluation of a potential policy aimed at tackling one (possibly) important source of disadvantage for low income families. There has long been a debate about the role of neighbourhood effects in determining outcomes; does living in a high poverty environment adversely affect your life chances, would individuals in these neighbourhoods be badly off anyway where ever they were, or do they live there because they are have bad economic outcomes? Any decent social scientist (or indeed anyone interested in evidenced based policies) will tell you that these explanations are extremely difficult to disentangle.

The MTO RCT involved providing families (4,600 of them) in public housing with vouchers to move to less disadvantaged neighbourhoods in 5 US cities (Baltimore, Boston, Chicago, LA and New York) in the mid 1990s. Conducted in association with the Department of Housing and Urban Development, the programme has been rigorously evaluated by a team of researchers including Jens Ludwig of Chicago and Larry Katz of Harvard. It goes without saying, or perhaps it doesn’t in Ireland, that the use of a lottery for voucher allocation is what makes this design so powerful. The final impact evaluation is currently being completed; previous academic papers are available below.

A summary of the findings is available here.

Essentially there was (perhaps surprisingly) little effect of moving to a better neighbhourhood on the economic outcomes of families, or the test scores of children. On the other hand, there were important differences in terms of both physical (in particular obesity and diabetes) and mental health between experimental and control groups. The experimental group also reported higher levels of life satisfaction. On this basis Larry Katz summarized the effects of the treatment as being more a case of “Moving to Tranquility” than “Moving to Opportunity”.

One other important aspect of this programme is a willingness on behalf of the organizers to engage with other researchers, provide data and debate the findings. This adds greatly to the credibility of these studies, something else which does not seem to have been grasped in Ireland. Making data publicly available also goes some way to alleviating concerns about the influence of those commissioning the research. For an example of this, see the following exchange in the American Journal of Sociology on MTO.

Clampet-Lundquist, Susan, and Douglas S. Massey. 2008. “Neighborhood Effects on Economic Self-Sufficiency: A Reconsideration of the Moving to Opportunity Experiment.” American Journal of Sociology 114 (1): 107–43.


This article revisits the Moving to Opportunity housing mobility experiment, which heretofore has not provided strong evidence to support the hypothesis of neighborhood effects on economic self-sufficiency among adults. The authors undertake a conceptual and empirical analysis of the study’s design and implementation to gain a better understanding of the selection processes that occur within the study. The article shows that the study is potentially affected by selectivity at several junctures: in determining who complied with the program’s requirements, who entered integrated versus segregated neighborhoods, and who left neighborhoods after initial relocation. Furthermore, previous researchers have not found an experimental treatment effect on adult economic self-sufficiency, relative to controls. The authors propose an alternative approach that involves measuring the cumulative amount of time spent in different neighborhood environments. With this method, they find evidence that neighborhood is associated with outcomes such as employment, earnings, TANF receipt, and use of food stamps.

What Can We Learn about Neighborhood Effects from the Moving to Opportunity Experiment? Jens Ludwig, Jeffrey B. Liebman, Jeffrey R. Kling, Greg J. Duncan, Lawrence F. Katz, Ronald C. Kessler, and Lisa Sanbonmatsu, American Journal of Sociology 114 (July 2008), 144-88.


Experimental estimates from Moving to Opportunity (MTO) show no significant impacts of moves to lower-poverty neighborhoods on adult economic self-sufficiency four to seven years after random assignment. The authors disagree with Clampet-Lundquist and Massey’s claim that MTO was a weak intervention and therefore uninformative about neighborhood effects. MTO produced large changes in neighborhood environments that improved adult mental health and many outcomes for young females. Clampet-Lundquist and Massey’s claim that MTO experimental estimates are plagued by selection bias is erroneous. Their new nonexperimental estimates are uninformative because they add back the selection problems that MTO’s experimental design was intended to overcome.

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