Adding more ingredients to your sandwich will make it slightly more delicious, but it will make it moderately harder to handle, according to the results of my Great Sandwich Survey*.

Back in June, I took what was going to be an idle lunchtime data exercise for myself and opened it up to Datablog readers to rate the deliciousness, structural integrity, and number of ingredients of their sandwiches. A total of 348 responses were received, which I've now analysed to determine the relationship between each sandwich variable, and some other things along the way.

The most popular ingredients included in the sandwich type field were cheese, which featured in 17.9% of sandwiches, and then bacon, at 16.5%. One reader may have been slightly confused, and entered "pasta" under the sandwich type – or perhaps they ate a spaghetti sandwich.



Click here for the graph on mobile.

To determine the relationship between structural integrity, deliciousness, and the number of ingredients I calculated the correlation between each pair, and then tested whether it was statistically significant or not.

There was no significant correlation between the deliciousness of a sandwich and its structural integrity.

There was however, a significant relationship between both deliciousness and the number of ingredients, and structural integrity and the number of ingredients.

Heatmap showing how sandwiches rated in the number of sandwich ingredients versus deliciousness. 1 is least delicious, 10 is most. Click here to enlarge . Illustration: Nick Evershed for the Guardian

As the number of ingredients increases, there is a weak increase in the tastiness of a sandwich. The correlation coefficient, r, measures the extent of the correlation between two variables. Values of 1 or -1 are strong, and values closer to 0 are weaker. I expected this to be a stronger relationship than it is, but I suspect it's being dominated by sandwiches with a few ingredients and strong flavours, such as the popular bacon sanger. Indeed, the average number of ingredients was 3.6.

Heatmap showing the relationship between the structural integrity of a sandwich. 1 is most flimsy, 10 more sound. Click here to enlarge . Illustration: Nick Evershed for the Guardian

And, not surprisingly, making sandwiches more elaborate makes them harder to handle. As the number of ingredients increased, the structural integrity decreased, with a negative correlation coefficient of -0.24.

Heatmap showing the structural integrity of a sandwich versus deliciousness. 1 is most flimsy, 10 more sound. 1 is least delicious, 10 is most delicious. There was no significant correlation between the two factors. and the number of ingredients. Click here to enlarge . Illustration: Nick Evershed for the Guardian

Interestingly, overall most people rated their sandwiches pretty highly. The average score for deliciousness was 8.2. I suppose people wouldn't buy or make bad sandwiches after they've done it once or twice. The average structural integrity rating was 6.9.

And if you're going to chime in with a comment along the lines of "Hey, I knew all this already!", sometimes these things need to be quantified despite anecdotal evidence. Also it's fun and delicious.

*Total number of responses was 348 from a self-selecting population on the internet, where anyone could have fed credible-looking false data into the form. I didn't have a blind set-up, control for bread type or difference in personal opinion, or any number of other factors. The actual statistical value of this poll is about as good as a potato, so I'm analysing the results with this rather large caveat – it's just a bit of fun!

