## Support #1159

### Weights for cross-sectional and longitudinal analyses

100%

**Description**

Dear Understanding Society Support Team,

I am using data from adult main interviews from all waves. I am estimating the effect of depression on party identification. I am analyzing the data both cross-sectionally and longitudinally. However, I am unsure about which weight(s) to use, also given the low number of clinically depressed individuals. Is it correct that in both cases, since I am using data from more than one wave, I should use a longitudinal weight? Also, by reading the User Guide, in Wave 6 there is a change in the definition of the cross-sectional population represented. If this somehow complicates the issue, I have no problem with analyzing data only from Wave 1 to Wave 5. Could you please give me some recommendations?

Many thanks and best wishes,

Luca

### History

#### #1 Updated by Olena Kaminska 6 months ago

Luca,

Thank you for your question.

If you are interested in estimates in a particular time point - you should use cross-sectional weights. In other words if you estimate the same model for each wave separately and you include only information from that particular wave in the model - you should use the cross-sectional weight from that wave.

If you are using information from across a few waves - you should use a longitudinal weight from the last wave in your analysis.

The change in definition at wave 6 relates to immigrants: from wave 6 'ui' weights include immigrants since 2009 but 'ub' weights don't include them. This is only relevant if you put together many cross-sectional estimates and compare them over time (e.g. looking at a trend). This does not influence longitudinal analysis. If you want to be sure to have comparable cross-sectional estimates (i.e. those that exclude immigrants since 2009) then you can use 'ub' weights throughout.

Hope this helps,

Olena

#### #2 Updated by Luca Bernardi 6 months ago

Dear Olena,

Many thanks for replying so quickly. That's very helpful. If I understand correctly, since I am using information from across a few waves, I can apply the "indinub_lw" weight. Is this correct?

Thanks and best wishes,

Luca

#### #3 Updated by Olena Kaminska 6 months ago

Luca,

Yes, the weight is correct, and it should come from the last wave that you use in your analysis. Note, 'ub_lw' weight is available for analysis from wave 2 onwards.

Olena

#### #4 Updated by Luca Bernardi 6 months ago

Dear Olena,

Sounds good. Many thanks again.

Luca

#### #5 Updated by Stephanie Auty 6 months ago

**Private**changed from*Yes*to*No***% Done**changed from*0*to*100***Status**changed from*New*to*Resolved*