In deductive causal generalization, internal validity, external validity, and construct validity are *equal* legs of a stool. Internal validity alone is literally meaningless without the other two.
Abstract:
The Credibility Revolution advances internally valid research designs intended to identify causal effects from quantitative data. The ensuing emphasis on internal validity, however, has enabled a neglect of construct and external validity. We show that ignoring construct and external validity within identification strategies undermines the Credibility Revolution’s own goal of understanding causality deductively. Without assumptions regarding construct validity, one cannot accurately label the cause or outcome. Without assumptions regarding external validity, one cannot label the conditions enabling the cause to have an effect. If any of the assumptions regarding internal, construct, and external validity are missing, the claim is not deductively supported. The critical role of theoretical and substantive knowledge in deductive causal inference is illuminated by making such assumptions explicit. This article critically reviews approaches to identification in causal inference while developing a framework called causal specification. Causal specification augments existing identification strategies to enable and justify deductive, generalized claims about causes and effects. In the process, we review a variety of developments in the philosophy of science and causality and interdisciplinary social science methodology.
I liked your stool analogy. A three-legged stool, favored for the old practice of handmilking cows, is an epitome of stability because of its' relationship to gravity.I do not understand all of what you present on complex topics. But, I am working on and thinking about it, as best my cranial capacity allows.
ReplyDeleteGravity is just one force...a second force can bring a third force for balance...for internal-external-between cosmic constructs...et all...
ReplyDeleteSure. Just as the configuration of the tripod brings stability, over gravity, The weight of the stool occupant adds further stabilization. Turn an Egyptian pyramid upside down (physically, impractical) and all that is lost. In this comparison, gravity favors the three legged stool. Is the third force absence of a hurricane wind? Just funnin' with you!
ReplyDeleteAs in the gravity of our atmosphere's with the validity of wind constructs in mind...keeping things moving...
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