A Note on the Inoperability Input‐Output Model

In this note, we propose some comments and some extensions of the inoperability input‐output model (IIOM), as recently proposed by Santos and Haimes (2004). In particular, we propose the use of some analytic tools capable of providing information on the reaction of sectors subsequent to a terrorist attack on infrastructure service sectors. These tools, namely, the field of influence and the multiplier product matrix, provide information on the way sectors react to a shock on the aggregate demand and/or to a (temporary or permanent) change of production function coefficients. Finally, using the 2003 65 sectors input‐output matrix for the U.S. economy, a simple empirical example is presented.