Control Function Corrections for Unobserved Factors in Differentiated Product Models
Unobserved factors in differentiated product models can generate severe bias in price elasticities. We develop a generalized control function method and specification test for this setting based on the nonparametric identification results from Petrin (2005), who shows the assumptions under which price functions can be inverted to obtain controls that condition on the part of the demand error that is not independent of price. Unlike using product-market controls, our approach does not require additive separability between observed and unobserved factors. We develop a ``hybrid'' approach that also loosens this restriction for that setting. We compare results across approaches on three data sets and demand specifications estimated elsewhere that span a range of markets and levels of aggregation, including automobiles (the original Berry, Levinsohn, and Pakes (1995) application), cable television, and margarine. The estimated elasticities are similar across the control function and product-market control approaches, and they both differ significantly from the uncorrected elasticity estimates, which are significantly biased up in every case
To our knowledge, this item is not available for
download. To find whether it is available, there are three
1. Check below under "Related research" whether another version of this item is available online.
2. Check on the provider's web page whether it is in fact available.
3. Perform a search for a similarly titled item that would be available.
|Date of creation:||03 Dec 2006|
|Date of revision:|
|Contact details of provider:|| Postal: Society for Economic Dynamics Marina Azzimonti Department of Economics Stonybrook University 10 Nicolls Road Stonybrook NY 11790 USA|
Web page: http://www.EconomicDynamics.org/
More information through EDIRC
When requesting a correction, please mention this item's handle: RePEc:red:sed006:856. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Christian Zimmermann)
If references are entirely missing, you can add them using this form.