Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
With the recent diffusion of broadband (BB) services, Internet protocol (IP) telephony is expected to spread significantly in Japan. This article investigates the demand for IP telephony by using conjoint analysis. Projecting IP telephony demand also contributes to Japanese info-communication policy discussions. Two points are made. First, IP telephony is still currently considered an optional supplement or an add-on service option of high-speed BB Internet access services in Japan rather than a close substitute of existing plain old telephone service (POTS). At this point, we find little evidence that many households will promptly forsake their fixed line service for IP telephony. Second, we conclude that the key condition for the proliferation of IP telephony is the complete guarantee of quality of service (QoS), including voice quality, number portability, fax usage and emergency access, comparable to or exceeding that of existing POTS.