Italian fisheries socio-economic data are collected through a specific sample survey which is conducted in accordance with specific and statically sound principles for the design, collection, processing and analysis of the data.
Sample data are collected by means of direct and face-to-face interview where a questionnaire is filled in. The interview, usually to the vessel’s owner, is conducted by a data-collector, who previously – before beginning the survey – received an in-depth training. The variables to be collected are listed in a questionnaire according to a rational sequence and consist of most pertinent data required for a socio-economic assessment of a fishery.
After this first phase, data is transferred into an electronic form through an ad-hoc web platform (www.rilevazionecosti.org). This facilitates the application of a specific and organised quality check workflow which can be simplified in a sequence of micro and macro-level editing, second-stage interviews with the vessel’s owners, and statistical analysis, one of which through a specific tool called NICODA (Nisea Controllo Dati). NICODA allows also for the imputation of the missing values.
Following the completion of the earlier sequences the next step is to raise the sample data up to the total population through statistical inference where specific estimators are utilised (Horvitz–Thompson estimator and Sen-Yates-Grundy variance estimator).
The statistical quality indicators are calculated in accordance with the EU data collection procedures and the Italian National Programme for the Collection of Fisheries Data. The main statistical quality indicator considered is the coefficient of variation which is calculated through an ad-hoc procedure run through a specific tool devised by Nisea and called NISE (Nisea Statistical Engine).
The estimates are further checked through a tool called NIBAT (Nisea Banca Dati).
