Maybe the previous author had the same confusion.
http://lema.rae.es/drae/srv/search?id=hTXhUCMS1DXX2DI3MWRd empírico, ca. (Del lat. empirĭcus, y este del gr. ἐμπειρικός, que se rige por la experiencia). 1. adj. Perteneciente o relativo a la experiencia.
No, that's not what it means at all:
http://www.merriam-webster.com/dictionary/empirical
None of the three definitions mention "structured observation", and the second definition directly contradicts that assertion.