For each of the 400 firms in our sample, we manually collect data on outstanding debt from public, bank, and non-bank private lenders from the footnotes to each firm's financial statements for each reporting year from 2000 to 2012. To capture the incremental choice of debt source for our sample firms, we use Nexis UK to manually search for announcements of issuances of public debt, bilateral and syndicated bank debt and non-bank private debt.

How difficult and time consuming has been to manually gathering data in this context? 

What are the disadvantages in this method? What are the advantages?