data vs data volume

AJ   Mon Sep 25, 2006 3:33 am GMT
"If the market data volume also includes incorrect market data,...."

Hi, The above sentence is a part of technical writing sentence.

What I wonder is..
Is it possible that 'market data' alone can also represent 'market data volume'?
Is the 'volume' part is mandatory to mean what the sentence is meaning?
Isn't it redundant??

This kind of questions keep occuring to me quite often, so please help me.