Experimental Design Details
At KERBHOLZ Onlineshop you can buy products from four different main categories: watches, sunglasses, jewellery and interior. By clicking on one of the four categories, a visitor is directed to the so-called category page, where all the products in the respective category are listed and can be compared with each other based on their design, price, model name and wood type. This category page remains identical for both treatments. If a user clicks on a certain product to take a closer look at it, she is forwarded to the product detail page, where she will find many details about the respective product (size, short description, more photos, etc.) and a button through which she can add her selected model to the shopping cart. The design of the product detail page now varies between the two treatments. For treatment group 1, differently coloured buttons are displayed directly above the add-to-cart button, showing the user in which variants her chosen model is also available (for example, in a different wood type, with a differently coloured watch strap or with a different plating). However, this is not new information, since these variants were also already displayed on the category page. Thus, group 1 sees some of the available options twice. By clicking on a variant button, the user is forwarded form the initially selected product to the detail page of the now selected model variant. To treatment group 2 these buttons are not shown. Otherwise the pages shown to the two groups do not differ. Since all available model variants are also displayed on the category page, the size of the choice set remains unchanged across the two groups. Hence, the only difference between the treatments is that group 2 is only once confronted with the available options, namely on the category page. Contrary to this, a user in group 1 will first see all existing choices on the category page and in addition to that she also sees the availability of other options very similar to the model originally selected, just above the add-to-cart button. This could distract her from her original decision (namely to add the selected model to the cart). It is examined whether the add-to-cart rate differs between the two treatments.