Bog standard? Study seeks most effective toilet training methods

The Guardian

04-03-2025

Storybooks about potties, underpants featuring superheroes, rewards for doing a wee: toilet training is a rite of passage for any child. But with the average age of toilet training steadily creeping upwards, scientists are now hoping to crack the question of which methods are most effective.
A team at University College London is inviting people from across the world to share their experiences and techniques as part of the Big Toilet Project. The ultimate aim is to uncover evidence that could help parents toilet train children earlier and reduce the massive contribution that disposable nappies make to landfill waste.
'I understand this is a sensitive and difficult issue for many families,' said Prof Mark Miodownik, a materials scientist who is leading the project. 'I found toilet training my kids very difficult. We are doing this research because there is a potential win-win situation here. Finding effective and safe ways to toilet train children earlier helps the child, helps the parents, reduces costs to the family, and reduces plastic waste.'
Available evidence shows that the average age of toilet training has crept up over the past century. One US paper reported that the mean age of toilet training in the 1950s was 29 months, but by the 2000s only 40 to 60% of children had completed toilet training by 36 months. In the UK, US and many European countries, the milestone appears to be occurring ever later, and most recently there was public outcry when a teacher survey suggested that one in four children starting school in England and Wales were not toilet trained.
The team say that they want to move away from a 'potty shaming' tone that often accompanies discussions of the issue and find evidence to underpin more supportive policies to help parents and tackle the environmental impact.
In 2021, the UN reported that disposable nappies were one of the biggest contributors to plastic waste globally. In the EU alone, it was estimated in 2019 that 34bn single-use nappies are used every year, resulting in around 6.7m tonnes of waste annually.
The project aims to uncover the factors driving the trend and the reasons for wide variations between countries and demographic groups.
'Anecdotally, there's much lower toilet training ages in countries with lower per capita wealth,' said Dr Ayşe Allison, a behavioural psychologist at UCL. 'In the US, Australia and western Europe the age has gone up. People are hypothesising and theorising why this might be, but we just don't really know.'
A possible factor is that modern nappies are so absorbent that children don't know when they are wet, meaning they lack the necessary sensory cues to learn when they need the toilet.
'Nappies are just so darn good,' said Sarah Timms, of Education and Resources for Improving Childhood Continence (Eric), a children's bowel and bladder charity, which is not part of the project. 'How aware are you of these bodily functions if you don't feel it?'
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In the past, she added, the sheer effort involved in washing terry cloth nappies meant parents were highly motivated to toilet train their children.
Children also spend more hours in childcare, and there have been changes in parenting style, with a greater emphasis on a child-led approach. Cutbacks on health visitors and the mass closure of children's centres have reduced access to support for parents. Many also increasingly rely on social media, which does not always provide sound advice on the topic and can create unrealistic expectations about what is a gradual learning process rather than a quick transition for most children.
'There are these influencers online that people take to be absolute gospel,' said Miodownik. 'When we look at them, we don't find they are particularly evidence-based.'
Parents who are currently toilet training are initially being invited to complete a five-minute survey and there is an option to record monthly progress in a toilet training diary.