So far this chapter has separately examined the key factors thought to influence food waste, examining inter- relations between the factors as appropriate. This has suggested that although there are household-level differences between households within all of the factors, and in some cases per capita level differences too, underlying all of these is the size of the household. When you control for this through a simple per capita analysis, the factors that seem to show differences at a household level such as ethnic origin and age are no longer important.
To investigate further, a test was carried out to measure the degree of statistical association between the avoidable food waste produced and the key factors measured in this research, such as age of the head of household and the number of people in the household. Data which is available on the households’ job occupation, ethnicity composition and so on are categorical variables33 and therefore to measure the existence and strength of association with the amount of food waste produced a technique known as stepwise multivariate discriminative analysis was used. One of the problems with these variables is that they are intrinsic to the respondents and the effect of one (e.g. age) on food waste production may be confounded by other unmeasured but related variables that will impact food waste production (e.g. health). With stepwise discrimination analysis, variables should be independent from each other, and as already seen there appear to be relationships between the demographics. So, for example, the age of the respondent is linked to lifestage while the number of occupants is linked to household composition. A number of analyses were conducted using different variables that did not appear to have a high interrelationship in order to obtain an overview of statistical association. This means that the combined results of the discrimination analyses should be treated as indicative rather than statistically valid.
33Categorical variables are those that come in categories (e.g. social grade, tenure) as opposed to linear variables (e.g. height,
The food we waste
198
Figure 201 Strength of relationship of different variables to the amount of avoidable household food waste generatedsignificance of variable on weight of avoidable food waste
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 occupation grouping ethnicity lifestage job status household composition age of respondent household size correlation
The above chart illustrates the strength of association derived from the multivariate analyses. It identifies the number of occupants in the household as having the strongest correlation34 with household avoidable food waste production followed by the age of the main shopper in the household (which has a negative impact so that as age increases household food waste decreases). Tenure was rejected by the analysis as having a significant impact on avoidable household food waste. Note that this analysis was carried out at a household rather than a per capita level.
8.11
Summary of chapter
There are some significant differences between the amounts and cost of food wasted amongst different types of household. Key differences in terms of avoidable food waste are summarised below.
Larger households waste the most while single-occupancy households waste the least. However, on a per capita basis, it is single occupants that waste the most and the majority of these are of retirement age. Although there is a hypothesis that the war generation will be less wasteful, this seems to be the case only where households consist of two or more adults.
Although larger households waste more, they do not do so proportionally (a household of two does not waste double the amount of a single-person household, for example).
Households where the food shopper is younger waste the most while households where the main shopper is older waste the least; this is most pronounced in the 16 to 24 age group at the one extreme and the 65-plus age group at the other. However, on a per capita basis, individuals in households where the person with responsibility for food shopping is aged 55 to 64 waste the most avoidable food.
Multiple-occupancy households where the head of household is retired waste less than households where the head of household is either in employment or is unemployed/sick.
The food we waste
199
Households where the head of household is dependent on the state waste the most while households wherethe head of household is professional waste the least. However, it is apparent that this finding arises because the households with a lower disposable income have a greater likelihood of comprising of families with children under 16 years.
Asian households waste the most while White British households waste the least, but analysis suggests this is due to larger household sizes rather than anything related to ethnic background per se. Indeed on a per capita basis, individuals in multiple-occupancy Asian households contribute the same amount of waste as individuals within similar White British households. Individuals living in White non-British households waste the most on a per capita basis.The food we waste
200
9
Links between food waste and other
waste-related attitudes and
behaviour
9.1
Introduction
This chapter takes information on the average financial cost and weight of the uneaten food items that are produced at a household level and presents it according to other waste-related attitudes and behaviour. This analysis illustrates where statistical associations may exist but does not prove that any type of attitude or behaviour has a causal relationship with the amount of food waste generated at a household level. For example, householders that recycle a lot of their household waste may place less food waste in their bin for collection by the council, but this may be due to other factors such as only buying the amount of food that they know will be consumed, or it may be that they only prepare and serve the amount of food that will be eaten.
An analysis of the average weight and cost of all food waste and the weight and cost of avoidable food waste is provided. Avoidable food waste is food that could have been eaten if it had not been allowed to go mouldy or spoilt or if it had not been left over on a plate at the end of a meal, for example. Avoidable food waste excludes items that could not have been consumed such as used teabags or meat bones and waste that some people choose not to eat such as potato or carrot peelings or bread crusts. Unless otherwise indicated, the data presented in this chapter represents an estimate of the food waste that is thrown away via all methods of disposal using the model described in Chapter 1 (see Section 1.4) where nine tenths of food waste is thrown away via the household’s residual bin and/or in the council’s separate food waste container. It should be noted that because the weights have been converted from grammes to kilogrammes and rounded and annual costs have been rounded to the nearest £10, rounding anomalies may occur.
The attitudes and behaviours covered in this chapter include:
extent to which households compost at home (Section 9.2);
attitude to recycling (Section 9.3);
amount of self-declared effort put into recycling (Section 9.4);
self-declared extent of recycling (Section 9.5); degree of commitment to recycling (Section 9.6); and
The chapter also compares householders’ perceptions of the amounts of food wasted with the amount actually wasted as measured through this study. The influence of socio-demographics such as age and housing type on food waste production has already been covered in Chapter 8.