I am new to R and usually rely on stata.
I have a considerably large data frame, it contains data from a broad range of surveys and years, each with their own types of classifications and answers. The variables have not been standardised. The data is at an Individual level.
Questions I have are the following:
How can I aggregate the surveys? How can Identify the number of surveys which have provided information on a particular variable i'm interested in like education?
Thank you very much,