An on-site survey is a short question put to a visitor directly during a visit or after completing an action. It supplements analytics data with something you can never read from the numbers – the reason for the behaviour. There are three proven uses: a question after purchase, what nearly stopped the order being completed; a question when leaving a pricing page, what was missing for a decision; and a question to new visitors, what they were looking for. Brevity is key, ideally a single open question, and a non-intrusive display that does not get in the way of browsing. The answers come from a small sample, but recurring themes show up quickly and become the basis for hypotheses. It is worth showing the results to the sales and customer teams too, since they confirm or disprove their assumptions.
See also: Hypothesis in CRO, Exit intent, NPS – Net Promoter Score.