The 7-11 Milk Experiment: How Does Site Design Affect Revenue?

by Christine Perfetti

At UIE, we’ve spent a great deal of time trying to assess how elements of a site design affect revenue. In all of our recent studies of e-commerce sites, we’ve based our research on what we refer to as the 7-11 Milk Experiment.

What is a 7-11 Milk Experiment? Here’s the scenario: Imagine I had a way to identify when someone has run out of milk. I pick them up in my car and drive them to the nearest 7-11. And just to make sure everything goes well, I give them the money to buy milk. How likely is it that that store can sell milk in this scenario? When I’ve asked people this question, almost all respond that it’s close to 100%. If the store does not end up selling to the user, there’s clearly something wrong with their experience on the site.

In our research, we mirror this type of experiment online. We find people who need products, bring them to sites that have the products they want, and give them money to buy the products. What did we find?

In our latest study, users only purchased 30% of the time! So, what was happening here? We found that on most of the sites, users just couldn’t find what they were looking for and that the site’s organization was to blame.

From watching users shop, we’ve seen that they use a progressive process. Users move from one stage to the next, as they try to purchase a product. One of the biggest priorities in our current research agenda is to identify where in the purchase process users fail, such as the Home Page, the Product Lists pages, or the Target Content pages. By understanding how these different stages and types of web pages work, we hope to learn a lot more about building usable sites.