(1999 10 ) 00.3.8 (7) ( ) 1767 1773 ( ) ( ) (cf. 1997) Leibenstein (1950), Rohlfs (1974), Katz & Shapiro(1985, 1986a), Farrell & Saloner (1985, 1986) 1
2 (cf. 1995) (1) (Call Externality) (2) (Network Externality) / 2 Leibenstein (1950) Rohlfs(1974) 1.1 Leibenstein(1950) (Morgenstern 1948) (Von Neumann) (Non-additivity) (Leibenstein 1950) (External Effect) (Bandwagon Effect) (Snob Effect) (Conspicuous Consumption) (Veblen Effect) 1 1 (1) (2) 2
(d i ) (p) (D d i d i (p, D) ( d i / D 0) 2 d 1 D 1 d 2 D 2 d 2 d 1 p 1 p 2 q 1 (p 1, D 1 ) q 2 (p 2, D 2 ) q 1 q 1 (p 2, D 1 q 1 q 2 E 1 E 2 d 12 ( ) 2 1.2 Rohlfs (1974) Artle & Averous (1973) (Rohlfs 1974) 2 f w p fw p fw p w f w=a(1-f) af(1-f)=p ( 3 ) p 0 f S f L 0 f L f S (Viability) (Start-up) 2 Rohlfs(1974) (1992) 3
f S (Critical Mass) (Low Introductory Price) 3 Katz & Shapiro (1) (2) (3) (Katz & Shapiro K&S) (1) (Installed Base) (2) K&S 2 K&S(1985) K&S(1986b) 4 4
2.2 Katz & Shapiro(1985) K&S(1985) (1) 2 1 2 (2) (r) (y) (V) (r+v(y)) V(y) (3) ( ) ( ) (4) (Fulfilled Expectations Cournot Equilibrium) FECE K&S(1985) (1) (Z) (C) (I) (Z C Z I 5 3 (2) ( ) (S) (W= +S) (C) (I) ( C I, S C S I, W C W I ) (3) ( C I ) ( W W C W I ) ( W) (4) F ( F W) (5) 5 3 FECE Z/n = (A+V(Z))/(n+1) n A r V(Z) 5
2.2 Katz & Shapiro (1986a) K&S(1986a) (1) 0 1 2 (2) 2 ( 1 2 ) N Z V(Z)-( ) V(2N) V(N) V=V(2N) V(N) (3) A( ) B( ) C H C L C=C H C L A 1 C L 2 C H B 1 C H 2 C L (C) 1 A 2 B N C C =2N C W C =2N(V(2N)-C L ) 4 (I) 2 1 2 ( V C) 5 2 1.1 1 A AB 6 A 1 p 1 C H -3 V A 1 N( C-3 V) B 2 q 2 C H - V 2 N( C- V) 1.2 1 B BB 7 B 1 q 1 C L + V 1 (Z C Z I ) 4 1 A 2 B C H C 5 B 2 AB AA 2 (V(N)-C L V(2N)-C H V C) 6 BB B N(q 1 - C + V)+N( C+ V) 1 B N(q 1 - C + V)+N( C+ V) N( C- V) q 1 C -3 V A 1 p 1 C -3 V A 1 N( C-3 V) BB AB 2 (V(2N)-C H =V(N)-q 2 ) q 2 =C - V 2 N(q 2 -C L )=N( C- V) 7 AB BB 1 (V(N)-C L =V(2N)-q 1 ) q 1 =C L + V 1 N(q 1 -C H )=N( V- C) AB BB 2 (V(N)-C H =V(2N)- q 2 ) q 2 =C + V 2 N(q 2 -C L )=N( C+ V) 1 B N( C- V) N( V- 6
N( V- C) B 2 q 2 C H + V 2 N( C+ V) B 1 C 3 V 2 2 ( V C) 8 A B 1 2 A 1 p 1 C H - V B 1 q 1 C L - V p 1 q 1 B ( BB ) B BI A B I W I B B W 1 6 (1) (3 V C) B (Second Mover Advantage) (2) (2 V C) B ( B 0) (3) (2 V C) ( W ) (4) F W F 1 6 2.3 Katz & Shapiro K&S (1986b) (Sponsor) (ex. ) K&S(1986b) C)+N( C+ V) C 3 V 8 A 2 N( V- C) B 2 N( V+ C) A 1 A N (p 1 -C L ) + N ( V- C) A 1 p 1 =0 p 1 =C H - V B 1 q 1 C L - V 7
2 2 (1) (2) (3) K&S (1992) (Insufficient Friction) (1) (2) (3) Farrell & Saloner (Farrell & Saloner F&S) 2 (1) (Excess Inertia) (2) (Excess Momentum) 2 F&S(1985) F&S(1986) 7 3.1 Farrell & Saloner (1985) F&S(1985) 2 2 8
2 ( ) (1), (2), (3), F&S 3 (1) (i=0) (i=1) 8 (, ) 9 (2) (2, ) (1, ) (2, ) (1, ) (3) 3 A1 A2 A3 (i) (i<i 1 ) A3 (i 1 <i<i 2 ) A2 (i 2 <i) A1 10 i 1 A2 A3 i 1 =0.25 i 2 A1 A2 i 2 =0.6 0.5 i 0.6 0.6 0.5 11 9 i (2, )=0 (1, )=-1 (2, )=-2+4i (1, )=-3+4i i 0 1 10 A1 i 1 (1, )+(1- i 1 ) (2, ) A2 i 2 (2, )+(1- i 2 ) (2, ) A3 i 2 (2, )+(1- i 2 ) (1, ) A2 A3 i 1 =0.25 A1 A2 i 2 =0.6 11 Farrell & Saloner 9
2 8 3.2 Farrell & Saloner (1986) F&S(1986) ( U V) n(t)=1 N(t)=t x U(x)=bx V(x)=dx( b d) (t T*) T (r ) 12 U(T) bt/r+b/r 2 1 2 U 0 (T) bt/r V(T) d(t- T*)/r+d/r 2 V 0 (T) d(t-t*)/r 2 (1)V(T*) U 0 (T*) d/b T*r (2)U(T*) V 0 (T*) T*r+1 0 2 d/b T*r G G 0 d/b 1+T*r 13 9 14 (1) 12 U(T)= T U(N(t))exp(-r(t-T))dt U 0 (T)= U(N(T)) T exp(-r(t-t))dt V(T)= T U(N(t)-N(T*))exp(-r(t-T))dt V 0 (T)= U(N(T)-N(T*)) T exp(-r(t-t))dt 13 G= (V(t)-U(t))exp(-r(t-T))dt-bT*/ r 2 =(2(d-b)-2rbT*)/r 3 1 T* T* 2 10
(T*r d/b 1+T*r) (2) (1+T*r d/b) 9 3.3 Farrell & Saloner F&S (1988) 3 (Coordination Game) (Cheap Talk ) (1) (2) F&S (1992) F&S (1992) (1) (2) (3) F&S (1992) Journal of Industrial Organization (1992)/ Journal of Economic Perspectives (1994)/ International Journal of Industrial Organization (1996) 14 Farrell & Saloner (1986) (Preannouncement) 11
( ) ( ) (cf. 1996, Ida 1999) ( ) ( ) (Universal Service) ( ) ( ) ( ) 12
(1995) 156.5: 395-415. (1996) 37.1 31-81. (1992). (1997). (1995). Artle, R. and C. Averous (1973), The Telephone System as a Public Good: Static and Dynamic Aspects, Bell Journal of Economics and Management Science 4: 89-100. Farrell, J. and G. Saloner (1985), Standardization, Compatibility, and Innovation, Rand Journal of Economics 16.1: 70-83. Farrell, J. and G. Saloner (1986), Installed Base and Compatibility: Innovation, Product Preannouncements, and Predation, American Economic Review 76.5: 940-955. Farrell, J. and G. Saloner (1988), Coordination through Committees and Markets, Rand Journal of Economics 19.2: 235-252. Farrell, J. and G. Saloner (1992), Converters, Compatibility, and the Control of Interface, Journal of Industrial Economics XL: 9-35. Ida, T. (1999), Network Externality and Monopolistic Pricing, Konan University and University of Illinois Working Paper. Katz, M.L. and C. Shapiro (1985), Network Externalities, Competition, and Compatibility, American Economic Review 75.3: 424-440. Katz, M.L. and C. Shapiro (1986a), Product Compatibility Choice in a Market with Technological Progress, Oxford Economic Papers Special Issue on the New Industrial Economics:146-165. Katz, M.L. and C. Shapiro (1986b), Technology Adoption in the Presence of Network Externality, Journal of Political Economy 94.4: 822-841. Katz, M.L. and C. Shapiro (1992), Product Introduction with Network Externalities, Journal of Industrial Economics XL: 55-83. Leibenstein, H. (1950), Bandwagon, Snob, and Veblen Effects in the Theory of Consumers Demand, Quarterly Journal of Economics 64: 183-207. Morgenstern, O. (1948), Demand Theory Reconsidered, Quarterly Journal of Economics 62: 165-201. Rohlfs, J. (1974), A Theory of Interdependent demand for a Communications Service, Bell Journal of Economics and Management Science 5: 16-37. 13
1 Leibenstein(1950) Rohlfs(1974) 2 p d 1 d 2 p 1 E 1 p 2 E 2 d 12 0 q 1 q 1 q 2 q 14
3 p 0 f S f L f 4 Katz & Shapiro Katz & Shapiro(1985) Katz & Shapiro(1986a) 15
5 Katz & Shapiro(1985) (n+1) Z na+nv(z) na+ V(y i ) na Z I Z C Z 1 Katz & Shapiro(1986a) #2: BB V C #1.2: BB V C 3 V #1.1: AB 3 V C BI N C 2N V N( C- V) B 0 N( C-2 V) N V I N C 2N V 2N( C-2 V) N C 2N( C- V) 4N V W I N(2V(2N)-C H -C L ) N(2V(2N)-C H -C L ) 2N(V(N) -C L ) W N C N C 2N V 16
6 Katz & Shapiro(1986a) V 2 V 3 V C BB BB AB B 0, W 7 Farrell & Saloner Farrell & Saloner(1985) Farrell & Saloner (1986) 2 Farrell & Saloner(1985) (i=0) (i=1) -2-3 2 1-1 0-1 0 17
8 Farrell & Saloner(1985) 2 (2, ) 1 (1, ) 0 0 (2, ) -1-1 (1, ) -2-3 0 i 1 =0.25 0. 5 i 2 =0.6 0.75 1 A3 A2 A1 9 Farrell & Saloner(1986) rt* 1+rT* d/b 18