MORE ABOUT MEASUREMENT

 

Weighting Data Exercises For Further Study

 

 

Weighting Data

 

Sometimes, most typically in survey research, some cases in a dataset may be overrepresented, while others will be underrepresented.  This may be done deliberately in order to ensure that there will be sufficient numbers of members  of  small groups to permit reliable analysis.  For example, a survey of members of different political parties might deliberately oversample minor party identifiers.  In other instances, inadvertent but known over and undersampling may occur.  For example, we may know from available census data that our survey has either over or undersampled rural residents.

 

In either case, it will be necessary to weight cases to correct for these discrepancies.  Data files often come with one or more weight variables that can be used for this purpose.