For any two brands of a frequently-bought product in a given time-period, the proportion of buyers of one brand who also buy the other brand is generally directly proportional to the total number of buyers of that brand. Such duplicated buyers of two brands buy each brand with an average frequency which tends to be a fixed fraction of that with which all buyers of each brand buy it.
BuckS., “Consumer Purchasing Patterns as a Guide to Market Potential,” Admap, 4 (1968), 214–8.
3.
ChatfieldC., EhrenbergA. S. C., and GoodhardtG. J., “Progress on a Simplified Model of Stationary Purchasing Behaviour,” Journal of the Royal Statistical Society, A 129 (1966), 317–67.
4.
ColemanJ. S., Models of Change and Response Uncertainty, Englewood Cliffs: Prentice-Hall, 1964.
5.
CunninghamRoss M., “Brand Loyalty—What, Where, How Much?” Harvard Business Review, 34 (1956), 116–28.
6.
EhrenbergA. S. C., “The Practical Meaning and Usefulness of the NBD/LSD Theory of Repeat Buying,” Applied Statistics, 17 (1968), 17–32.
7.
EhrenbergA. S. C., “The Discovery and Use of Laws of Marketing,” Journal of Advertising Research, 9 (1969), 11–7.
8.
EhrenbergA. S. C. and GoodhardtG. J., “The Amount Bought by Above-Average Buyers,” Journal of the Market Research Society, 10 (1968), 157–71.
9.
EhrenbergA. S. C., “Pack-Size Rates of Purchasing,” Proceedings of XXI ESOMAR Congress, Opatija, Brussels: ESOMAR, September, 1968, and Applied Economics, 2 (1970), in press.
10.
FrankR. E., “Brand Choice as a Probability Process,” Journal of Business, 35 (1962), 43–56.
11.
GrahnG. L., “The Negative Binomial Distribution Model of Repeat-Purchase Loyalty: An Empirical Investigation,” Journal of Marketing Research, 6 (1969), 72–8.
12.
KuehnA. A., “Consumer Brand Choice—A Learning Process?” in Kuehn, et al., eds., Quantitative Techniques in Marketing Analysis, Homewood, Illinois: Richard D. Irwin Co., 1962.
McPheeW. N., Formal Theories of Mass Behavior, Glencoe: The Free Press, 1963.
15.
PyattG., “A Model of Brand Loyalties,” Proceedings of the 1968 CEIR/SCS Symposium on Model Building in Business and Industry, in KendallM. G., ed., London: Griffin (in press).
16.
SchuchmanA., “Are There Laws of Consumer Behavior?” Journal of Advertising Research, 8 (1968), 19–28.
