The food waste calculator is based on the extensive 2010–2012 Foodspill food waste diary study by Natural Resource Institute Finland. This quantitative study surveyed household food waste for a period of two weeks. In addition to measuring food waste and providing their background information, the participants answered over a hundred questions related to their shopping behaviour and food waste. Unlike, for example, a composition study, a diary study helps expose correlations behind food waste.
The questions for the food waste calculator were selected by statistical methods from a wide breadth of material to generate a food waste prediction of highest possible precision with a limited set of questions. Responses to the questionnaire have a proven correlation with total waste. There might not be direct causality, as the correlation may be due to underlying parameters. The estimated prices for foodstuffs are also based on the Foodspill study, updated with current consumer price data from Statistics Finland.
The climate impact of food loss and waste results from producing unnecessary food, especially from farming and its biological processes such as emissions from ruminants’ digestion of feed and nitrous oxide emissions from agricultural soils. The estimated climate impact of food waste is based on several studies on the climate impact, or carbon footprint, of various food chains by Natural Resource Institute Finland, their client assignments, and similar international studies and their research materials. The carbon footprint estimates were made on the product group level.