The following weighting metrics describe the impact of weighting
on your data. The closer your weighting efficiency is to 100%, the more closely
your weighted data resembles your actual data, and the better you can
understand the weighting.
The weighting metrics can be viewed below each question in a crosstab
report.
The following table explains the values displayed.
| Values
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Weighted Base
The total number of responses after weighting is applied.
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Effective Base
A value derived from the weight values applied to each
participant and calculated using the following formula:
The effective base is useful for understanding the impact
of weighting on your data. An effective base that is close to the unweighted
base indicates weighted data that more closely resembles actual data, and
therefore a better weight scheme. If weighting is inflating the responses from
a particular group unduly, the effective base will be much smaller than the
unweighted and weighted bases.
-
Unweighted Base
The total number of responses before weighting is applied.
-
Weighting Efficiency
A value derived from the following calculation:
Weighting efficiency is useful for understanding the
impact of weighting on your data. The closer your weighting efficiency is to
100%, the more closely your weighted data resembles your actual data, and
therefore the better you can consider your weighting. If weighting is inflating
the responses from a particular group unduly, your weighting efficiency will be
significantly less than 100%. Reconsider your weight scheme if weighting
efficiency is less than 40%.
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