@article{deBoer:272357,
      recid = {272357},
      author = {de Boer, P. M. C. and Harkema, R.},
      title = {AN ALGORITHM FOR MAXIMUM LIKELIHOOD ESTIMATION OF A NEW  COVARIANCE MATRIX SPECIFICATION FOR SUM-CONSTRAINED MODELS},
      address = {1986-12},
      number = {2099-2018-3262},
      series = {REPORT 8639/A},
      pages = {39},
      year = {1986},
      abstract = {Maximum likelihood procedures for estimating  sum-constrained models like demand systems, brand choice  models and so on, break down or produce very unstable  estimates when the number of categories n is large as  compared with the number of observations available T. In  empirical studies this difficulty is mostly resolved by  postulating the contemporaneous covariance matrix of the  dependent variables to be equal to a2(I - n-il 1 1). In  this paper we develop n n a maximum likelihood procedure  based on a contemporaneous covariance matrix which allows  that the variances per category may be different, while the  number of observations required is substantially less than  the number that would be required in the case of a  completely unrestricted contemporaneous covariance matrix.},
      url = {http://ageconsearch.umn.edu/record/272357},
      doi = {https://doi.org/10.22004/ag.econ.272357},
}