Merge or append?

[Beenish Amir]

Hello! I am working on survey data that was collected in 3 waves. I want to know how to merge data sets in which variables have been added over each wave and number of observations have also increased. Please help

[Carlo Lazzaro]

Beenish:
welcome to this forum.
Ii's hard (for me, at least) to help with no details about your query.

[Beenish Amir]

Sorry, this is my first post so i am finding it hard to explain. I am working on survey data that was collected over 3 years, the individuals who were surveyed remained the same each year and more individuals were surveyed in the subsequent years the questions that were asked in the survey were increased in the 2nd and third year as well. Now I am unsure as to how merging or appending will affect the data set.

[William Lisowski]

It seems likely that you will want to analyze your data as panel data. To use Stata's tools for analyzing panel data, you want one observation for each combination of indid and wave. To do that, you need to append your two datasets.

For a good explanation of this, you should read the "Remarks and Examples" section of the "Introduction to xt commands" entry in the Stata Longitudinal-Data/Panel-Data Reference Manual PDF included with your Stata installation and accessible from the Stata Help menu.

[Beenish Amir]

okay thanks, I will try that

[Marcos Almeida]

Simple put, append will add observations, whereas merge will add variables. Please type help merge followed by help append to see exemples.