Boer, P. M. C. de; Harkema, R.; Soede, A. J. - In: Applied Economics Letters 3 (1996) 1, pp. 45-48
Maximum likelihood procedures for estimating market share models break down or produce very unstable estimates when the number of brands is large as compared with the number of observations. The reason behind this phenomenon is that the estimate of the contemporaneous covariance matrix of the...
