430 Studying How E-Markets Evaluation Can Enhance Trust in Virtual Business Communities
applied evaluation instrument. The e-market recommendation problem is therefore a multi-
criteria decision making one.
According to the multi-criteria decision making literature (Roy, 1996; Jacquet-Lagreze &
Siskos, 2001), each criterion is a non-decreasing real valued function defined on CxS as
follows:
gi : C × S → K / s → gi (s ) ∈ K
(2)
where gi (s) is the evaluation of the e-market s on the ith criterion ( i =1,..., n ). Thus, the multi-
criteria evaluation of an e-market s∈ S is given as a vector g(s) or
g ( s ) =[g 1( s ), g 2( s ),..., gn (s )]
We have previously assumed that the evaluation instrument to
be used for evaluating all e-markets in the context of the VC will be the same. In this version of
the algorithm, we choose the WebQual instrument (Barnes & Vidgen, 2002) and therefore the
criteria set is: Usability (g1), Information Quality (g2), and Service Interaction Quality (g3).
The developers of WebQual claim that these criteria are independent and sufficient for
measuring the satisfactions of users from e-commerce resources. The above criteria take
values from a 7-point scale {1,.,7}, where ‘1’ is the lower value of the criterion, and ‘7’ the
higher one. Since each criterion gi is a non-decreasing real valued function, and that there is
no uncertainty during the decision making, the total utility of an e-market s∈ S for a business
partner c∈ C can be expressed as:
uc(s)=∑i3=1wicgic(s)
(3)
where gci(s) is the evaluation value of e-market s on criterion gi, and wci is a weight indicating
the importance of criterion gi for the particular business partner c, with:
∑3 wc = 1
(4)
i=1 i
The linear function of Eq.(3) is the simplest and most popular form of an additive value
function, according to the principles of Multi-Attribute Utility Theory (MAUT). Others could
include an ideal point model, dependencies and correlations, as well as diminishing utility
forms (Price & Messinger, 2005).
Assuming that there has been a subset of business partners M in the overall community C (that
is M ⊆ C ) that has evaluated a subset of e-markets K from the whole population of available
e-markets S (that is K ⊆ S), then the following hold:
• For each business partner m ∈ M that has evaluated an e-market k ∈ K , this evaluation is
m mmm
defined as the vector g g 1 ʊ,g2 ', g3 ' 2∙∣, and there is also a set of importance