28 414 MASS. INST. TECH.104- 2 4 74JUN 14 DCVitY LiSRASY WORKING PAPER ALFRED P. SLOAN SCHOOL OF MANAGEMENT A MARKET SHARE THEOREM David E. Bell* Ralph L. Keeney=^ John D. C. Littlef 704-74 March, 1974 MASSACHUSETTS INSTITUTE OF TECHNOLOGY 50 MEMORIAL DRIVE CAMBRIDGE, MASSACHUSETTS 02139 «A5S. INST. TECH. 7424JUN A MARKET SHARE THEOREM David E. Bell* Ralph L. Keeney^ John D. C. Littlef 704-74 March, 1974 *International Institute for Applied System Analysis, Laxenburg, Austria School of Management & Operations Research Center=|=M.I.T., Sloan part grant from NABISCO, Inc. for researchThis work was supported in by a in marketing science. .M4\4 no.lD4-74 19741JUL LiBKArtltS 1. T. ^rt. Abstract marketing models use variants of the relationship: Market shareMany marketing effort divided by total marketing effort. Although theequals can be assumed directly, certain insight is gained by derivingrelation more fundamental assumptions as follows. For a given customerit from competitive seller has a real valued "attraction" with thegroup, each attraction is non-negative, two sellers with equalproperties: (1) (2) market share, the market share for a given sellerattraction have equal (3) same manner if the attraction of any other seller iswill be affected in the increased by a fixed amount. that if the relation between share andA theorem proven states assumptions, then share equals attractionattraction satisfies the above marketing factors can be assembleddivided by total attraction.