Pareto what?

I was in a meeting today when a BI domain expert questioned me about the Pareto principle used to efficiently reduce the volume of data warehouse quality issues. "I beg your pardon sir, is this an Italian restaurant that you are talking about?" The Pareto principle is a 80-20 rule which states that 80% of the issues are caused by 20% of the users or bugs. In this case the Pareto principle tells us to focus on the important 20% to eliminate as much as 80% of the issues. This will increase the turn around time to optimize the data warehouse.