Our simple grocery basket comparison turned into a huge hit. Here’s how we do it
In 2022 South Africans all over the country were feeling the pinch. The basic fuel price and the consumer price index were at highs of R26.74 per litre and 7.8% respectively. Even the usual chats in our office switched from “What did you do over the weekend?” to “Have you noticed how expensive everything is becoming?”.
That was when I decided to look at the different prices of staple foods in South Africa between major retailers. I was looking for proof that even a basket of basic items was becoming unaffordable for many South Africans. Over the long term, I also had an idea to document these prices in order to be able to look back on increases from month to month and year to year.
After sorting through the data from the first comparison I already found something interesting. Woolworths, a grocery store that has a reputation for being quite expensive, took the cheapest slot. How could that be? It turned out Woolworths was very competitive with its pricing of staples which made for an interesting chart.
Although Woolworths has only taken the most affordable rank three times since we started this project, it’s still usually in one of the cheaper spots which really surprises people and gets them talking. In fact, the store’s placing is usually one of the biggest talking points on our charts.
Our first grocery basket comparison was published in June 2022, and since then, the project has become a monthly feature at The Outlier. We run as a bar chart where each bar represents a basket total from a different store, accompanied by a brief contextual write-up that our newsletter subscribers receive.
After the first few months of publishing this project, we received email requests from stores asking us to add them to the list. This was when we realised that not only were consumers taking notice but shop managers were, too. What started as a comparison between four stores — Checkers, Woolworths, SPAR and Pick n Pay, grew to six, with the addition of Shoprite and Food Lover’s Market. And we still receive requests to this day.
Soon the data project also caught the attention of two popular television news shows in South Africa, Fokus and Newzroom Afrika and the radio station Hot102.7 FM, among others. That was quite a big deal for our small newsroom.
This is how we do it:
Around the 24th day of every month, my colleague Gemma Ritchie and I go to stores around Pretoria and Johannesburg where we document the prices of the same basket of goods from the six major South African retailers.
Here’s our grocery list:
700g loaf of Albany Superior Sliced White Bread, or store brand
2-litre store brand sunflower oil
2.5kg Iwisa maize meal
2.5kg Selati white sugar
2-litre store brand milk
2kg Tastic rice
2.5kg Snowflake cake flour
175g bar of Dettol Herbal Soap
9-pack of 2-ply toilet paper, average price over all brands
We take photographic proof of the in-store prices, then input the prices into a shared spreadsheet. It’s important to note that we exclude any kind of discounts; this is to make sure that we are making a fair comparison because not all South Africans have access to these loyalty card discounts. We also list any alternatives we used if, for some reason, the regular brand that we track was not available.
Once the spreadsheet has been completed, I put the data into Flourish to create a basic version of the column chart. I save that as an SVG and import it into Figma.
Here’s a quick guide to getting started with Flourish and Figma.
The first draft
All of the final editing is done in Figma, where we have standard design styles which we follow. This includes specific fonts, font sizes and colours. (Here’s a bit more about how and why we do our charts like this.)
The final version
In our newsletter and on our website, the chart is accompanied by a brief article that introduces the project and lists the goods and methodology. The only thing that changes is the bit of text above the chart which describes our findings for that month.
Problems along the way
When our first two posts were published in June and July we used the 18-pack of toilet paper for our price comparison. After some back and forth with our readers — many argued that the toilet paper pack we were looking at wasn’t in proportion to the other items in our basket — we decided to change it to the nine-pack of two-ply toilet paper from August 2022.
Another issue — not all stores keep the same brands. You can’t make a fair comparison between stores if you aren’t comparing apples with apples. We first came across this issue when it came to comparing the prices of toilet paper from store to store. Some shops only offered store-brand versions of toilet paper, others only offered store brands that were not of the same quantity as what we were comparing and other times there was no store-brand version on offer at all. Using alternatives every time was skewing our data because some brands were much cheaper than others.
I resorted to calculating the average price of the product from each store by adding up all the toilet paper brands on offer and dividing the sum by the number of brands. For example, Checkers has three different brands of nine-pack, two-ply toilet paper on offer. So, I added the cost of all of those brands and divided that number by three. This gave me a better comparable price to work with.
Read more about our methodology here.
As data journalists, we might sometimes look for credible, neat and ready-made datasets. But this is just one example of how creating your own dataset can turn into a pretty popular long-term project.
If you’re interested in following our grocery basket journey visit The Outlier’s website or subscribe to our newsletter.
Media Hack Collective publishes data journalism on The Outlier — including a growing collection of charts — offers data journalism training across the African continent, and publishes a number of data-backed newsletters.
