Materials and methods for the bio-oil

The method chosen was the mail-survey, through a questionnaire sent to all the license-holders (Lochart 1984). Because of the reluctance shown by some corporations,if to provide these lists or not, in the fear of privacy laws, total privacy has been guaranteed, in the name of science. At the same time, the self-research of addresses was begun, through lists of partakers to national and international fairs, Pagine Bianche (the national list of phone numbers), the internet etc. The only regions where there aren't holders for bio-oils are Valle d'Aosta, Trentino Alto Adige and Friuli Venezia Giulia. The most farms are in Tuscany (24%) Apulia (17%), followed by Calabria (11%) and Sicily (10%). The holders were sent a questionnaire with 24 closed questions, together with a motivational letter- that explained this research (Dillman 1974). Anonymousness and the collective use of data were guaranteed. Holders had an envelope with stamp and address, ready to be sent back.
In June 2005 the questions were sent and after twelve weeks there were 151 replies. The amount of replies was different from region to region: this determines some gap between the data and the objective situation. Furthermore as for 12 cases (7.9%) of the repliers the region wasn't indicated and it was impossible to deduce it from the postal print. On the whole there were 22.7% of answers, that is a considerable number for this kind of survey. The length of the questionnaire may have caused few answers, but not meaningless. The information were grouped as for the three big areas usually used in these researches: north, south and isles. This allows to make the analysis taking into consideration the structural peculiarities of the olive oil sector.