There is a correlation (good linkage) between EDO and famous international tests such as IELTS, TOEFL, TOEIC, etc. So if you work hard on the EDO levels, it is very likely that you will get good results when taking those tests. See the correlation table below.

Examination Correlations With English Discoveries Online*

* Based on information from "Using English for Academic Purposes - a Guide for International Students", Andy Gillett, Department of Inter-Faculty Studies, University of Hertfordshire, Hatfield, UK. (2002)