A method for calculating changes in regression coefficients and inverse matrices corresponding to changes in the set of available data
Leo Törnqvist · Scandinavian Actuarial Journal · 1957
Extract When we have made a regression analysis, for instance on the basis of time series, it is often of interest to know how the results would change if we take into account observations made later on. Because it seems that the whole work of solving the normal equations must be made over again, we seldom continue the calculations by taking into account later information. It is, however, easy to find the adjustments required by a method developed in this article. It is possible to get time series showing the development of the regression coefficients without formidable work. We can in this way get a deeper insight in the problem to be studied than by making the regression analysis only once for all. If the purpose of the regression analysis is to obtain formulas to be used for forecasting, time series of regression coefficients give a better starting point than if we only have regression coefficients for a certain period.