On Tue, 25 Jun 2002, Anil Rupasingha wrote: > I have a question on the estimates of an spatial error model (SEM). The > parameters in the OLS with the presence of spatial dependence in the error > term will still be unbiased but inefficient. Does this mean that > parameters of the SEM model and the OLS should be numerically identical? Or > is this an asymptotic property? Thanks for any replies.
Certainly not numerically identical. The standard errors will be biased if the error autoregressive parameter is different from zero. The coefficients will be unbiased only if the spatial autocorrelation of the variables in the model is fully accounted for in the error process, as far as I recall. If you are not in a tightly controlled experimental setting, there will usually be some spatial dependence which is not accounted for, leading to bias in the coefficient estimates too. Roger -- Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Breiviksveien 40, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93 e-mail: [EMAIL PROTECTED] and: Department of Geography and Regional Development, University of Gdansk, al. Mar. J. Pilsudskiego 46, PL-81 378 Gdynia, Poland. -- * To post a message to the list, send it to [EMAIL PROTECTED] * As a general service to the users, please remember to post a summary of any useful responses to your questions. * To unsubscribe, send an email to [EMAIL PROTECTED] with no subject and "unsubscribe ai-geostats" followed by "end" on the next line in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list * Support to the list is provided at http://www.ai-geostats.org
