Get in touch

+44 (0) 28 9099 2882


Extrapolation misleads from user kneads

Extrapolation misleads from user kneads

Many major pizza brands run promotional campaigns every few years to broadcast the results of their “the nation’s favourite pizza” and “nation’s favourite pizza topping” surveys.  It is simple and highly effective PR.  It generates easy and inoffensive discussion, it engenders a response by those who read it (yuck – WHO eats pineapple on a pizza?) and it fills up lots of newspaper column inches for time–starved editors trying to get their hands on readable copy.  It’s simple and effective marketing with tangible results for brand owners operating in a busy marketplace.

Pizza Hut last ran their promotion in 2017 and many UK newspapers, predominantly the red–tops, published the results.  Here are the most popular pizzas in their stores:

Meat Feast

Four Star pizza ran a similar initiative in Ireland a few years later and discovered the following favourite toppings:


Do any of those results surprise you?

The reason I ask is because pizza toppings are a subject on which everyone has an opinion and yet only people who work for pizza brands or have recently read a newspaper article on the topic will confidently know the survey results.

As part of delivering UX research training, I’ve asked hundreds of people about pizza toppings over the years and consistently people share that they’re not surprised pepperoni is top of the pile, they are surprised that a plain pizza is the most popular one in Pizza Hut and mushrooms being in the top 5 blows their minds!  Mushrooms – are you mad?!

My interest lies however in why people are surprised.

To explain why, let’s consider how the human brain works when faced with a question it doesn’t know the answer to but has some knowledge or experience of, explained through the medium of pizza.  For people who don’t know the nation’s favourite pizza topping they often start with personal questions, ‘what is my favourite pizza topping’ or ‘what pizzas are eaten first when we make pizza for family tea’ before broadening out their thoughts ‘we had a pizza and beer evening at work last week – what did people eat and what was left over‘. That then becomes a basis for identifying popular toppings and from there guesses are made and expectations set around what the nation’s favourite topping might be. In other words, people consider their own experiences and extrapolate them out to the nation at large.

The exercise is light–hearted and carried out to generate discussion, but it does highlight the flawed logic of extrapolation.  Extrapolation falls fouls to the availability bias which says that we over–value information which is immediately available to us.  In the case of pizza, we over–value our own experiences and preferences of pizza and apply them to the populace at large.  This is based on an enormous assumption that my circle of friends and family are exactly representative of the nation – and that’s almost definitely not the case.

Somewhat ironically this might have been a factor in the recent closure of Domino’s Pizza in Italy.  What research or insight drove the Michigan–based fast food chain to believe there was an appetite for its Americanised offering in the birth–place of traditional pizza?

Extrapolation explains the human tendency to assume that people we know in a minority (for example in terms of their sexuality or religion) somehow represent or are like all people within that minority – that the characteristics of those people we know are common to all.

In the context of software, extrapolation is expressed in the tendency to assume that the people we spend time with – our colleagues, our boss, our industry peers – are representative of a wider group of users. It tempts us to conclude that those we invest our days with are somehow user proxies, and that we can garner understanding about how users think by considering their view.

This is dangerously flawed thinking and needs to be consciously resisted. We know that most people in the digital industry can complete tasks that 95% of the population can’t, we know that digital leaders such as Amazon and Google work hard on culture to avoid making assumptions about users and we know that design needs to work not just in the boardroom but on the sofa, in the coffee shop and at the bus stop.

In short, we are not the user, but more importantly the reason UX exists as a discipline is specifically because we are not the user. If we were the user, or we were like the user, or our colleagues were like the user we as an industry could save hundreds of millions of dollars every year, because we could stop engaging with users and just ask our colleagues, our bosses and our peers for their preferences and design for them.

We often don’t consciously extrapolate. The availability bias is rarely deliberate – it’s just the brain’s flawed default means of thinking.  Our response to it must however be intentional and it starts by recommitting to the fundamental truth which underpins all good design.

We are not the user.

By Gareth Dunlop

Gareth formed Fathom in 2011 and has been in the business of design performance for over two decades.

View more insights by Gareth

Like to read more of our insights regularly?

Receive our monthly insights newsletter straight to your inbox.

To prove you’re a human please rewrite the following into the box below.

Latest from the blog

Our latest views and ideas

Our Cookie Policy

Find out more I accept

Like most websites, ours uses cookies to make sure you receive the best experience possible. These cookies are safe and secure and do not store any sensitive information. To continue, please accept the use of cookies.