(i.e. index size). Moreover,
there are distinguished two main stream approaches to evaluate effectiveness: systemand
user-centric. System-centric evaluation is the most common and typically uses
traditional basic relevance measures like precision and recall (Manning et al., 2008, p.
142). Relevance is normally assessed by human-judgment or by using a standard
document collection like TREC (Voorhees & Harman, 2005).