estimating network efiects in mobile telephony germany toker doganogluyand lukasz grzybowski z may 2006 abstract this paper we analyze demand for telecommunications services the period from january 1998 to june 2003 during time subscriber base grew exponentially by about 700 while prices declined only moderately 41 our conjecture is that alone cannot account such rapid difiusion and have uenced evolution of industry put view test using publicly available data on subscriptions price indices churn rates approximate sales levels which enable us use standard methods investigate efiect size demands estimates a system functions indicate played signiflcant role keywords discrete choice jel classiflcation l13 l96 would like thank volkswagen stiftung generous flnancial support made research possible all errors are ours ycenter information economics university munich akademiestr 1 i 80799 email stat uni muenchen de zcorresponding author katholieke universiteit leuven
