On the history of potential outcome models (wonkish)

31 Jul, 2013 at 10:24 | Posted in Statistics & Econometrics | 1 Comment


My understanding of the history is as follows. The potential outcome framework became popular in the econometrics literature on causality around 1990. See Heckman (1990, American Economic Review, Papers and Proceedings, “Varieties of Selection Bias,” 313-318, and Manski (1990 American Economic Review, Papers and Proceedings, “Nonparametric Bounds on Treatment Effects,” 319-323.) Both those papers read very differently from the classic paper in the econometric literature on program evaluation and causality, published five years earlier, (Heckman, and Robb, 1985, “Alternative Methods for Evaluating the Impact of Interventions,” in Heckman and Singer (eds.), Longitudinal Analysis of Labor Market Data, Cambridge, Cambridge University Press) which did not use the potential outcome framework. When the potential outcome framework became popular, there was little credit given to Rubin’s work, but there were also no references to Neyman (1923), Roy (1951) or Quandt (1958) in the Heckman and Manski papers. It appears that at the time the notational shift was not viewed as sufficiently important to attribute to anyone.

Heckman’s later work has attempted to place the potential outcome framework in a historical perspective. Here are two quotes somewhat clarifying his views on the relation to Rubin’s work. In 1996 he wrote:

“The “Rubin Model” is a version of the widely used econometric switching regression model (Maddalla 1983; Quandt, 1958, 1972, 1988). The Rubin model shares many features in common with the Roy model (Heckman and Honore, 1990, Roy 1951) and the model of competing risks (Cox, 1962). It is a tribute to the value of the framework that it has been independently invented by different disciplines and subfields within statistics at different times.” p. 459
(Heckman, (1996) Comment on “identification of causal effects using instrumental variables”,
journal of the american statistical association.)

More recently, in 2008, he wrote:

“4.3 The Econometric Model vs. the Neyman-Rubin Model
Many statisticians and social scientists use a model of counterfactuals and causality attributed to Donald Rubin by Paul Holland (1986). The framework was developed in statistics by Neyman (1923), Cox (1958) and others. Parallel frameworks were independently developed in psychometrics (Thurstone, 1927) and economics (Haavelmo, 1943; Quandt, 1958, 1972; Roy, 1951). The statistical treatment effect literature originates in the statistical literature on the design of experiments. It draws on hypothetical experiments to define causality and thereby creates the impression in the minds of many of its users that random assignment is the most convincing way to identify causal models.” p. 19
(“Econometric Causality”, Heckman, International economic review, 2008, 1-27.)

(I include the last sentence of the quote mainly because it is an interesting thought, although it is not really germane to the current discussion.)

In the end I agree with Andrew’s blog post that the attribution to Roy or Quandt is tenuous, and I would caution the readers of this blog not to interpret Heckman’s views on this as reflecting a consensus in the economics profession. The Haavelmo reference is interesting. Haavelmo is certainly thinking of potential outcomes in his 1943 paper, and I view Haavelmo’s paper (and a related paper by Tinbergen) as the closest to a precursor of the Rubin Causal Model in economics. However, Haavelmo’s notation did not catch on, and soon econometricians wrote their models in terms of realized, not potential, outcomes, not returning to the explicit potential outcome notation till 1990.

Relatedly, I recently met Paul Holland at a conference, and I asked him about the reasons for attaching the label “Rubin Causal Model” to the potential outcome framework in 1986. (now you often see phrase, “called the Rubin Causal Model by Paul Holland”). Paul responded that he felt that Don’s work on this went so far beyond what was done before by, among others, Neyman (1923), by putting the potential outcomes front and center in a discussion on causality, as in the 1974 paper, that his contributions merited this label. Personally I agree with that.

Guido Imbens

1 Comment

  1. Hello Professor,

    All my apologies for this awful written english,

    Im pursuing my claim about the marxian characteristic of Alfred Schutz’s theoretical programme by postulating that what Schutz called “construction (constitution) of the first degree”(subjective meaning) is merely the concept of the negation (the real) and “reconstruction” (objective meaning) refers to “the negation of negation”(construction of the construction).

    Alfred Schutz’s attempt was to confer to Weber’s sociology a strong subjective phenomenological basis in order to pointed out furthermore the subjectivism of his sociological theory.

    Therefore, the strong subjectivism of Weber’s sociology confirmed his deep marxian feature.

    Subjective meaning(Weber’s capitalist mind, the real) as opposed to objective meaning (protestant ethic of capitalism as ideology, the formal) undoubedtly draws the distinction between subjective critical materialism and dialectical objective materialism, construction versus reconstruction means negation versus the negation of the negation that is to say negative dialectic(Adorno) versus materialist dialectic.

    Thank you.


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