Estimation algorithms in the calculation of effective area of pressure balances

We discuss methods for analysing calibration data to estimate the effective area of a pressure balance. These include the so-called P- and Delta P-met hods, and a method in which the estimate is made by solving a generalized r egression problem that reflects more correctly the error structure in the m easurement data. We compare these methods, both from a theoretical point of view and on simulated data, and show that the differences in the parameter estimates can be significant compared with the claimed measurement uncerta inty.