Quick, reliable quantitative data to back up or challenge design assumptions. We often recommend and use design experiments at the later stages of a project to ensure we’re on the right track.
Tree testing gives a quick, reliable and quantitative insight into whether there are structural problems with a site. A robust sample size means that the results can indicate what could cause your users in the future and from there you can proactively fix them before they become an issue.
Click testing is way of providing quantitative certainty around specific key interactions. It shows what doesn’t work and also, offers real validation on what does work.