This is often expressed in terms of a loss function where the loss to society is expressed as a weighted average of squared deviations of inflation from its target and of output from its potential level. The squaring of the deviations ensures 8 that deviations on either side of the target are treated equivalently as losses.
The weights, a and 1-a, indicate the relative intensity of the public's distaste for deviating from their preferred rates of inflation and output.