About Sample Balancing

Note: Run|Sample Balancing cannot be selected unless your job and data files are open.

The goal of the “Sample Balancing” module is to provide a weight for each respondent in the sample such that the weighted marginals on each of a set of characteristics matches preset values of those marginals. This process is sometimes called “raking” or “rim weighting.” The most common procedure used to produce these weights is “iterative proportional fitting”, Though “iterative proportional fitting” has the nice property of converging to a set of nonnegative weights, these weights do not have any optimal properties (such as the minimization of some measure of goodness of fit.)

See the Sample Balancing section of Help|Statistical Reference for more detailed information about Sample Balancing and the techniques that are being used.

Sample balancing allows you to use up to 10 different variables and as many as 20 numeric values within each variable (each value can include a range of up to 99 codes) the combination of which cannot exceed 50,000,000:

For example:	Variable 1	Variable 2	Variable 3
	Value 1 = 20%	Value 1 = 25%	Value 1-10 = 50%
	Value 2 = 20%	Value 2 = 25%	Value 11-20 = 25%
	Value 3 = 20%	Value 3 = 25%	Value 21-98 = 25%
	Value 4 = 20%	Value 4-9 = 25%
	Value 5 = 20%
Total Levels =	5	4	3

5x4x3 = 60 (much less than 50,000,000)

If you have respondents in your data that have a weight of zero, you can choose to calculate the sample balancing weight on the original sample size or a reduced sample size (exclude those respondents with a weight of zero).
If you have respondents with negative weights, you can replace those with a value of your choosing (default is 0.001).
A new file will be created, jobname.sbv if you are using variable data (see Sample Balancing: Variable data) and jobname.sba if you are using ASCII data (see Sample Balancing: ASCII data), that stores your sample balancing specifications.
Simply load the new data file (if applicable) or use the open data file with weights added and enter the weight variable or record/column location into Setup|Banners|Edit Banner|Weights.
Sample Balancing also creates its own report file showing you the minimum and maximum weights and how many respondents, if any, have a weight of zero.