Average Causal Response with Variable Treatment Intensity / Joshua D. Angrist, Guido W. Imbens.

Format:

Book

Author/Creator:

Angrist, Joshua D.

Contributor:

National Bureau of Economic Research.

Imbens, Guido W.

Series:

Technical Working Paper Series (National Bureau of Economic Research) no. t0127.

NBER technical working paper series no. t0127

Language:

English

Subjects (All):

Econometric models.

Physical Description:

1 online resource: illustrations (black and white);

Place of Publication:

Cambridge, Mass. National Bureau of Economic Research 1995.

Cambridge, Mass. : National Bureau of Economic Research, 1995.

Summary:

In evaluation research, an average causal effect is usually defined as the expected difference between the outcomes of the treated, and what these outcomes would have been in the absence of treatment. This definition of causal effects makes sense for binary treatments only. In this paper, we extend the definition of average causal effects to the case of variable treatments such as drug dosage, hours of exam preparation, cigarette smoking, and years of schooling. We show that given mild regularity assumptions, instrumental variables independence assumptions identify a weighted average of per-unit causal effects along the length of an appropriately defined causal response function. Conventional instrumental variables and Two-Stage Least Squares procedures can be interpreted as estimating the average causal response to a variable treatment.

Notes:

Print version record

June 1995.