The word "miscalculation" refers to a mistake or error made when estimating or calculating something. It means that someone has made a wrong judgment or assessment, leading to an incorrect outcome or result. Full definition
Nick Clegg has said one of his biggest miscalculations of the coalition was sitting next to David... (totalpolitics.com)
Also unfortunate are our sources» accounts of what did Infinity in, which they said had more to do with miscalculations in toy manufacturing than with game quality. (kotaku.com)
Recent history shows, however, that even the top policymakers can make huge miscalculations on housing. (canuckpost.com)