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Question to store weights

See Weighting respondents for an overview of rim/target weighting.

This section describes where to store the weights for weighted data.

The weight for each individual record is stored in a float (floating point) question which may need to be added to the QDF.

If you need to add more records to the data after this question has been created you can use "Suspend" so that it won't be seen during data entry.

Float question described

A float question stores a number with a decimal point.  It is stored as digits in the data file and the decimal point will not always be in the same place.

The precision of a float number is 14 significant digits.  This means that only the first 14 digits (0-9) in the number are reliable.  For this reason float entries are normally allocated 15 digits to allow for the decimal point.

Individual weights are normally between 0 and 9, for example 0.5743865838473 or 5.7823974922645, so this size normally allows for 13 decimal places.  A very large weight of say 2765.4738264035 would only have 10 decimal places.

Create new

If you do not already have a float entry for the weight in the project you can create one with [Targets] [Question to store weights] [Create new].

The program will add a new float question to the project using data locations at the end of the record.  You will be shown the Entry details window and you can change the name or the size (number of data locations).

When you close the Entry details window you may be asked to extend the record length to accommodate the new question. You should answer "Yes" to this.

The new question is placed at the beginning of the project.

If you only intend to use one weighting scheme then you should leave the name as "Weight" because an entry with this name will automatically be used as the respondent weight. If you intend to have more then one weighting scheme then you will need a different question for each scheme to store the weights.

The individual weights will be stored in the data locations allocated to this new entry.

If you have used this option it is important to save the revised project with the new question added.  You will be prompted to do this when you close the Weight data window.

Use existing

If you already have a float entry for the weight in the project you can replace the weights in it with [Targets] [Question to store weights] [Use existing].

The individual weights calculated will then be stored in the data locations allocated to this existing entry.

Saving name

The name allocated for weighting is stored in the weighting XML file along with the targets set.

If you reload a weighting file then you do not need to tell the program which question to use, it will use the one named in the weighting file.

With the targets set and the float question to store the weights chosen you can calculate the weights.