The opposite of preweights (see Preweights) are postweights, which are applied after all other weights have been applied, and therefore have no effect on the way in which targets are reached. They are generally used to make a final adjustment to a specific item.

For example, you might have a survey was conducted in London and Inverness, and 200 respondents were interviewed in each city. The standard weighting might balance each group according to sex and age so that the samples match the patterns of the total populations in those cities. After this is done, you might apply a postweight to adjust the totals for each city into their correct relative proportions, where London has a much larger population than Inverness.