Diaries have been used to obtain national and subnational estimates of household food waste (HHFW) in several countries. Furthermore, diaries have been proposed as a method for tracking progress towards goals that include HHFW reduction. However, multiple studies have suggested diaries substantially underestimate HHFW. This paper collates and analyses data from five studies in which diary estimates of HHFW can be directly compared to other, more accurate estimates from waste compositional analysis (WCA). This analysis finds that all diary estimates for HHFW were lower than the corresponding WCA estimates, with the degree of underestimation ranging from 7% to 40%. Four main factors are likely to contribute to this underestimation: behavioural reactivity (people wasting less during the diary period), misreporting (not all items discarded being recorded), measurement bias (not all items are weighed) and self-selection bias (those completing a diary being different from the wider population). The study concludes that a) diaries are useful for obtaining approximate estimates of HHFW and detailed information on what, why, and where food is discarded, but b) diaries alone are not suitable for tracking HHFW over time or evaluating interventions designed to reduce the amount of HHFW (without substantial further research).

日记已被用于获取一些国家的国家和国家以下地区的家庭食物垃圾（HHFW）估算值。此外，已经提出了日记作为跟踪实现包括减少HHFW在内的目标进展的方法。但是，多项研究表明，日记大大低估了HHFW。本文整理并分析了五项研究的数据，其中可以将HHFW的日记估算值直接与废物成分分析（WCA）的其他更准确的估算值进行比较。该分析发现，所有对HHFW的日记估计值均低于相应的WCA估计值，被低估的程度在7％至40％之间。造成这一低估的因素可能有四个：行为反应性（人们在日记中浪费的时间更少），错误报告（并非记录所有丢弃的物品），测量偏差（并非称量所有物品的重量）和自我选择偏差（完成日记的人与更广泛的人群不同）。研究得出的结论是：a）日记对获取日记有用HHFW的大概估算值以及有关丢弃食物，原因和地点的详细信息，但b）仅靠日记不适合随时间推移追踪HHFW或评估旨在减少HHFW数量的干预措施（无大量进一步研究）。