This paper explores the potential of the Finnish Longitudinal Employer-Employee Data (FLEED) in the analysis of entrepreneurship. It is found that these data are excellent for analyzing a certain sort of self-employed individuals who exercise their profession on their own account.
Link
http://econpapers.repec.org/scripts/redir.pl?u=http%3A%2F%2Fwww.etla.fi%2Ffiles%2F1069_Dp920.pdf;h=repec:rif:dpaper:920