Purpose: The purpose of this paper is to assess the reliability of questionnaires as a method of quantifying household food waste (FW), thus providing context regarding the validity of existing Italian estimates. Design/methodology/approach: A total of 30 households were involved in a diary study that was conducted for one week. The participating households were first asked about their FW quantities in a questionnaire. Half of the households who filled their diaries properly were then audited through waste sorting analysis performed on their garbage. Non-parametric tests were used to test for differences in FW estimates between audited and non-audited households, as well as differences among estimates obtained through different quantification methodologies. Findings: Edible FW was estimated to be 489 grams per week based on questionnaires, and 1,035 grams per week based on diaries. In the audited sub-sample of households, FW estimates were 334 grams per week based on questionnaires, 818 grams per week based on diaries and 1,058 grams per week based on waste sorting analysis. Research limitations/implications: Given the small sample size in the present study, future studies can utilize larger samples to assess whether the differences identified in estimates can be replicated. Future studies can also inquire into the behavioral biases that led consumers to underestimate their FW. Practical implications: Results of the present study point against the use of questionnaires to quantify household FW, hence raising some doubt on the reliability of existent Italian estimates. Where waste sorting is unfeasible, the use of adjustment methods or diaries is suggested to better inform policies. Originality/value: This study is one of the first on FW quantification that tests three different methodologies on the same sample, and is the first to do so in Italy, where estimates are still very poor.

Food waste from households contributes the greatest proportion to total food waste in developed countries. Therefore, food waste reduction requires an understanding of the socio-economic (contextual and behavioural) factors that lead to its generation within the household. Addressing such a complex subject calls for sound methodological approaches that until now have been conditioned by the large number of factors involved in waste generation, by the lack of a recognised definition, and by limited available data. This work contributes to food waste generation literature by using one of the largest available datasets that includes data on the objective amount of avoidable household food waste, along with information on a series of socio-economic factors. In order to address one aspect of the complexity of the problem, machine learning algorithms (random forests and boruta) for variable selection integrated with linear modelling, model selection and averaging are implemented. Model selection addresses model structural uncertainty, which is not routinely considered in assessments of food waste in literature. The main drivers of food waste in the home selected in the most parsimonious models include household size, the presence of fussy eaters, employment status, home ownership status, and the local authority. Results, regardless of which variable set the models are run on, point toward large households as being a key target element for food waste reduction interventions.

About one third of all food produced for human consumption is wasted. Along with a lively debate on food loss and waste definition and quantification, growing attention is dedicated to the faceted dimensions of consumers’ food waste. Drivers, effects, and mitigating factors have been mainly studied in isolation, with limited attention paid to their interrelationships. This study aims to contribute to a better understanding of the underlying relationship between the causes of food waste and consumers’ perception of their role and of their concern on food waste effects and mitigating factors. The article draws on a survey submitted to 938 respondents while shopping at a supermarket in Italy in 2015. Data were processed by principal components to identify latent dimensions of consumer behavior, and a cluster analysis was performed to identify homogenous groups of consumers. Results emphasize the complexity of the relationship between consumers and food resources. They suggest that while consumers are aware about food waste as a global issue, they often fail to identify the individual contribution they might provide for its prevention and reduction. The article also detects three groups of consumers with different approaches to food waste management and a specific perception of the food waste phenomenon.