Technical Perspective for

When a data analyst runs some query to analyze her data, she often wants to ask some follow-up questions, about the result of the query. Why-questions take many shapes, and occur in many scenarios. Why is a particular tuple in the answer? Why is it not in the answer? Why is this graph decreasing? Why did we observe a sudden burst of error messages in online monitoring? Database researchers have noted the need for why-questions, and the literature contains several approaches, mostly tailored to specific applications. Despite the interest and the work in this area, there is currently no consensus of what an explanation to a query answer should be, and how one should compute it.