First up, you need to know which quiz we’re talking about. It’s this one, so if you haven’t done it, go ahead now and come back to us, we’ll wait.
Everyone back? Cool.
When we created our sustainability quiz, we didn’t make very many guesses. We hired quants – or quantitative analysts – you know, the ones who understand statistics and big data, make very fancy graphs, have titles like ‘risk analyst’ and know what derivative structuring and algorithmic trading means. They know their stuff.
So how did we get to your score?
First, we simplified the broad, complex world of sustainability down to five lifestyle categories: energy, food, consumption, investment and travel. In the quiz, all the questions we ask fall into one of these categories and help to determine your score.
Then we divide the questions into two other categories: behavioural and emissions. Because there’s no way to know exactly what your investment portfolio looks like and how many emissions you’re “responsible” for, investment only has the behavioural part.
Okay, got it. What’s next?
The CO2 scores are the most complicated part. For the CO2 score, we estimate the number of kilograms of CO2 you emit based on your answers. Let’s use an example to illustrate how it works.
For instance, for travel. If you answered that you drive a petrol car, we first convert your weekly petrol spend to litres of petrol using the average petrol price in your region. (i.e. CO2 is calculated using the amount of petrol burnt)
We convert that number to kilograms of CO2 per week using an emissions factor (we know, it’s starting to get maths-y. That’s why we let the quants do it). We then factor in whether you carpool, how often and with how many people to reduce your personal kg CO2 emissions.
So how do you reach a final score?
To get to your overall carbon measurements, we work out your total CO2 emissions in kilograms per week by adding the amounts in each category together. We then normalise this value based on other people in your region, to give you total emissions score out of 100.
For your total behavioural score, we weight each of your category scores to give you a total score out of 100. These weightings are based on the impact each category has on emissions as well as how much control you have in making that choice. For example, it's easier to eat less meat than it is to install a solar panel, so food is weighted higher than energy.
We then combine the two totals to give you a score out of 100. The higher the score, the closer you are to sustainable living. Once you have a score, we give you a badge. For instance, 0 - 50, the most common group, is awarded Ready to Learn, and the highest-scoring group, 90 – 100 is awarded Officially Saving the World.
You can also earn badges for specific behaviours like carpooling or eating fewer animal products.
And that's how it's done.
TLDR: With a lot of very complicated maths.