Treatment Effect Bounds: An Application to Swan-Ganz Catheterization

Jay Bhattacharya, Azeem Shaikh, Edward Vytlacil

NBER Working Paper No. 11263
Issued in April 2005
NBER Program(s):   HC

We reanalyze data from the observational study by Connors et al. (1996) on the impact of Swan-Ganz catheterization on mortality outcomes. The Connors et al. (1996) study assumes that there are no unobserved differences between patients who are catheterized and patients who are not catheterized and finds that catheterization increases patient mortality. We instead allow for such differences between patients by implementing both the bounds of Manski (1990), which only exploits an instrumental variable, and the bounds of Shaikh and Vytlacil (2004), which exploit mild nonparametric, structural assumptions in addition to an instrumental variable. We propose and justify the use of indicators of weekday admission as an instrument for catheterization in this context. We find that in our application, the Manski (1990) bounds do not indicate whether catheterization increases or decreases mortality, whereas the Shaikh and Vytlacil (2004) bounds reveal that catheterization increases mortality at 30 days and beyond. We also extend the analysis of Shaikh and Vytlacil (2004) to exploit a further nonparametric, structural assumption -- that doctors catheterize individuals with systematically worse latent health -- and find that this assumption further narrows these bounds and strengthens our conclusions.

download in pdf format
   (300 K)

email paper

The NBER Bulletin on Aging and Health provides summaries of publications like this.  You can sign up to receive the NBER Bulletin on Aging and Health by email.

This paper was revised on July 13, 2007

Machine-readable bibliographic record - MARC, RIS, BibTeX

Document Object Identifier (DOI): 10.3386/w11263


  • Bhattacharya, Jay, Azeem M. Shaikh, and Edward Vytlacil. "Treatment Effect Bounds under Monotonicity Assumptions: An Application to Swan-Ganz Catheterization." American Economic Review 98,2 (2008): 351–56.
  • Bhattacharya, Jay & Shaikh, Azeem M. & Vytlacil, Edward, 2012. "Treatment effect bounds: An application to Swan–Ganz catheterization," Journal of Econometrics, Elsevier, vol. 168(2), pages 223-243. citation courtesy of

Users who downloaded this paper also downloaded* these:
Heckman and Vytlacil t0259 Instrumental Variables, Selection Models, and Tight Bounds on the Average Treatment Effect
Klenow and Rodríguez-Clare The Neoclassical Revival in Growth Economics: Has It Gone Too Far?
Shaikh and Vytlacil t0307 Threshold Crossing Models and Bounds on Treatment Effects: A Nonparametric Analysis
Fox, Garfinkel, Kaushal, Waldfogel, and Wimer w19789 Waging War on Poverty: Historical Trends in Poverty Using the Supplemental Poverty Measure
Rajan and Zingales w5758 Financial Dependence and Growth
NBER Videos

National Bureau of Economic Research, 1050 Massachusetts Ave., Cambridge, MA 02138; 617-868-3900; email:

Contact Us