The control function approach (Heckman and Robb (1985)) in a system of linear simultaneous equations provides a convenient procedure to estimate one of the functions in the system using reduced form residuals from the other functions as additional regressors. The conditions on the structural system under which this procedure can be used in nonlinear and nonparametric simultaneous equations has thus far been unknown. In this note, we define a new property of functions called control function separability and show it provides a complete characterization of the structural systems of simultaneous equations in which the control function procedure is valid.
Authors
CPP Co-Director
Richard is Co-Director of the Centre for the Microeconomic Analysis of Public Policy (CPP) and Senior Research Fellow at IFS.
UCLA
Working Paper details
- DOI
- 10.1920/wp.cem.2010.2810
- Publisher
- IFS
Suggested citation
Blundell, R and Matzkin, R. (2010). Conditions for the existence of control functions in nonseparable simultaneous equations models. London: IFS. Available at: https://ifs.org.uk/publications/conditions-existence-control-functions-nonseparable-simultaneous-equations-models (accessed: 1 July 2024).
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