2.3. GfK Consumer Panel

Average data (averaged over the entire year 2014) on food prices for >2000 different food items as per the FCS, including fresh products, were received from Europanel based on the GfK ConsumerScan panel data (Gfk, Brussels, Belgium). The ConsumerScan panel was designed as a stratified sample from the population of private households in Belgium and included about 5000 households. The stratification is based on the household characteristics, age and household size of the reference person (i.e., number of people living in the household). The panel members recorded household purchasing behavior (and related shop-visiting behavior) with respect to a broadly defined group of products regardless of the place of purchase. An electronic measuring instrument was used for purchase registration. This instrument consists of a preprogrammed hand terminal with a 4-line display, a simple keyboard and an integrated scanner for barcode scanning. The purchase and visit data recorded by the respondents were sent to the Research Centre via the GSM network.

A template was prepared based on the GloboDiet^© based food classification of the FCS taking into account a range of different product characteristics (i.e., fresh/frozen/canned; full/semi skimmed/skimmed; dried/liquid; full sugar/light/no sugar). Average prices were received from Europanel based on this template and linked to the foods and ingredients consumed in the FCS after taking into account factors for edible parts and yield.

For foods in the FCS with missing prices, the price of the most similar food (in terms of nutritional quality) in the same food group was used. For some food items where prices were given by piece, a conversion was made to obtain the price per kg. For out-of-home meals, the costs of their ingredients were taken into account for the purposes of this study as no prices were available for those meals from GfK.