Challenge 25: Enhancing age checks with facial age estimation and Digital IDs

profile picture Rachael Trotman 6 min read
Woman considering a bottle of wine in a shop with the UK "Challenge 25" logo overlayed

‘Challenge 25’ is a scheme used by retailers who sell age-restricted products. It requires shoppers who are over 18 but look under 25 to show ID.

But why was Challenge 25 introduced and how can age estimation technology and Digital IDs strengthen age checks in today’s world?


The history of Challenge 25

In 2005, test purchases revealed that some retailers were selling age-restricted items to underage customers. This testing was part of the Government’s Alcohol Misuse Enforcement Campaign (AMEC).

Research commissioned at the time explored why these underage sales were taking place. The key finding showed that retail staff found it difficult to guess the age of a person, so they often made mistakes.

The British Beer and Pub Association (BBPA) introduced Challenge 21 in 2005. This was to address the challenges retail workers faced when guessing the age of customers. It provided retailers with a safety buffer should they incorrectly estimate the age of customers. The rationale behind the policy – if you incorrectly estimate someone as being over the age of 21 you are less likely to serve someone who is under 18.

The initial results were positive but the buffer increased from 21 to 25 in the hope that this would have a greater impact and be less likely to let under 18s purchase age-restricted items. National retailers voluntarily started using Challenge 25 in 2009.

Challenge 25 is not just for alcohol sales. It applies to all age-restricted items, including lottery tickets, knives and tobacco.


Limitations of human age estimation  

Studies have shown that people aren’t great at estimating ages. People often estimate age more accurately when assessing people within their own age range. But younger people tend to overestimate the age of older faces and older people tend to overestimate the age of younger faces. 

Additionally, when viewing lots of faces in succession, a person’s judgement can be influenced by the faces they’ve just seen.

Several factors affect the ageing process, which makes it challenging for humans to estimate the age of another person. Quality of diet and nutrition, adverse environmental conditions, use of narcotics, physical labour, stress and lack of sleep all influence our physical appearance. 

The research commissioned in 2005 also discovered that some staff worried about confronting customers and found it difficult to challenge people. The BRC’s crime survey revealed that retail staff face over 1,300 incidents of violence and abuse every day. One of the most common triggers is when staff ask customers for proof of age when buying alcohol.


Challenge 25 in action

When a shopper buys a bottle of wine at a supermarket, it’s standard practice for the checkout worker to estimate their age. After all, they need to be sure that the person they are serving is 18 or older. 

If the supermarket worker thinks the shopper is 25 or over, they can proceed and buy the wine. But, if they’re unsure, or think the customer looks younger than 25, they will ask the customer to show some ID.

This approach to checking age is something we are familiar with. We don’t question this method. We trust it to keep children safe from accessing age-restricted goods or experiences in-person.

The process of humans estimating age and then asking for ID demonstrates how age estimation and age verification work in tandem. These two methods complement each other and help businesses when selling age-restricted goods.

But there is a new approach to age estimation which can improve age checks further.


How facial age estimation technology and Digital ID can help retailers meet Challenge 25

Rather than a human estimating age, technology can do this instead.

Facial age estimation has automated the age estimation process. It can determine a person’s age from a facial image. The technology gives everyone a secure and private way to prove their age, without using identity documents.

Once a person’s age has been estimated, the facial image is deleted – protecting their privacy. The whole process is anonymous because the technology does not recognise anyone when it estimates their age. It determines age without collecting or storing any personal data. 

Facial age estimation is scalable, it does not show bias or personal favour, and it is more accurate. These things can be measured, reported and improved on.

The technology can also work with age thresholds. Many businesses selling 18+ goods or services opt for a threshold of 25 – in line with the Challenge 25 policy. This means the technology needs to estimate the age of someone as 25 or over for them to pass the age check.

Anyone who is estimated below this threshold could then use either a Digital ID app or a physical ID document to prove their age. This is how facial age estimation can work in tandem with age verification and support the Challenge 25 policy. 

Online retailers can also use this approach when selling age-restricted items. Customers who are over 25 could use facial age estimation to quickly and securely pass an age check. And for those under 25, they could use a Digital ID app to share a verified ‘over 18’ proof of age. This is more robust and accurate than asking customers to enter their date of birth or tick a box stating they are over 18. And it’s more private than asking customers to submit their identity document online as proof of age. 

We transparently publish the accuracy of our facial age estimation technology. This can give businesses and regulators more confidence in how effective the technology is – and help them decide on an appropriate safety buffer. As the accuracy of the technology continues to improve, the thresholds could be lowered. This would allow more people to use this privacy-preserving way to prove their age.

Digital age verification can help combat fake IDs

In 2023, a good fake ID can be challenging to spot. They are concerningly easy and cheap to get hold of. And they are usually designed using sophisticated technology that replicates an original ID’s security features. 

This makes differentiating a fake from an original with the naked human eye nearly impossible. This puts increasing pressure on retail workers and puts the business at greater risk of selling age-restricted goods to underage customers. 

Digital age verification, such as a Digital ID app, can strengthen these age checks. Customers can use the app to share an ‘over 18’ proof of age. Retailers can be confident the age of the customer is correct because this is verified when someone first creates their Digital ID. 

Customers who don’t wish to use a Digital ID or who don’t own a smartphone could show a physical ID instead. It’s about giving customers a choice in how they prove their age and making age checks more inclusive for everyone.

Facial age estimation and Digital IDs can strengthen age checks and help retailers adhere to the Challenge 25 policy. To find out how we could help strengthen age checks, please get in touch.