Weighting methods

Quantum is sufficiently flexible to allow more than one set of weights for a given set of respondents. Which set is applied is determined by options on the a, sectbeg, flt or tab statement or on the statements which create the individual rows or columns of a table. Each set of weights, however, will apply one weight for each respondent. There are two ways of calculating weights:

▪The weight for each respondent can be part of the data for that respondent, or it can be calculated in the edit and passed to the tabulation section as a variable.

▪The more common method of weighting is to define a set of characteristics and apply specific weights to respondents satisfying those characteristics.

The example above uses characteristic weighting, where the characteristics are age, sex and working status. Thus, all respondents who are women aged between 45 and 54 and who do not work outside the home receive a weight of 10,000/380.

The characteristics must be such that each record satisfies one unique set. Each respondent falls into one, and only one, set and no respondent is left out. Because of this, you must check all columns containing the characteristics and if necessary, correct any errors. For example, if one characteristic is sex and it is coded in column 6 of card 1, with a code of 1 for male and 2 for female, you must make sure that c106 is single coded with a ‘1’ or a ‘2’ only. It must not be blank, multicoded or otherwise miscoded in any way.

Any respondent who is present in the base of the weighting matrix but not in any other row or column of the matrix is given a weight of 1.0, and their record is printed in the print file with the message ‘unweighted’.