Filters are a powerful way to modify what you measure (and don’t measure) into particular Google Analytics reporting views. They are a bit like the segments available within your reports, but with one important difference – they permanently modify the data that flows into reports.
View-based filters permanently modify your data, so it is generally best to create an entirely new view to apply the filter to, unless you know what you are doing. This way you won’t be impacting data in your existing reporting views.
Check out the top Top 5 Filters for Accurate Analytics Data: http://www.lovesdata.com/blog/2014/top- ... analytics/