What We Know About Spreadsheet Errors

If you ever needed to know why we need human computer interaction as a subject this is it. 
I've heard rumours about this paper but never saw it before and I finally I have the link to th paper. This is a damming bit of information for the digital world. 

Close to 90% of spreadsheet documents contain errors, a 2008 analysis of multiple studies suggests. “Spreadsheets, even after careful development, contain errors in 1% or more of all formula cells,” writes Ray Panko, a professor of IT management at the University of Hawaii and an authority on bad spreadsheet practices. “In large spreadsheets with thousands of formulas, there will be dozens of undetected errors.”