  There are many indexes (measures or metrics) in Social Network Analysis
(SNA), like density, cohesion, etc. In this paper, we define a new SNA index
called "comfortability". One among the lack of many factors, which affect the
effectiveness of a group, is "comfortability". So, comfortability is one of the
important attributes (characteristics) for a successful team work. It is
important to find a comfortable and successful team in any given social
network. In this paper, comfortable team, better comfortable team and highly
comfortable team of a social network are defined based on \textbf{graph
theoretic concepts} and some of their structural properties are analyzed.
  It is proved that forming better comfortable team or highly comfortable team
in any connected network are NP-Complete using the concepts of domination in
graph theory. Next, we give a polynomial-time approximation algorithm for
finding such a highly comfortable team in any given network with performance
ratio O(\ln \Delta), where \Delta is the maximum degree of a given network
(graph). The time complexity of the algorithm is proved to be O(n^{3}), where n
is the number of persons (vertices) in the network (graph). It is also proved
that our algorithm has reasonably reduced the dispersion rate.
