Under COUNTER Release 5 (R5), there is a longer elapsed time for user sessions which may cause higher deduplication of download activity by the same user. 


So, a user could return to a previously accessed content page and have it counted twice in COUNTER Release 4 whereas in R5 it may only be counted once. 


Therefore, in COUNTER R5 there is a possibility of more deduplication causing slightly lower reported user activity which could be recorded as either an investigation or request depending on the content type.


To find out more about COUNTER Release 5 Code of Practice, please see Where can I find more information on the COUNTER Release 5 Code of Practice?