This paper presents an extended version of Goal-
Oriented Requirements Analysis Method called AGORA,
where attribute values, e.g. contribution values and preference
matrices, are added to goal graphs. An analyst attaches
contribution values and preference values to edges
and nodes of a goal graph respectively during the process
for refining and decomposing the goals. The contribution
value of an edge stands for the degree of the contribution
of the sub-goal to the achievement of its parent goal, while
the preference matrix of a goal represents the preference of
the goal for each stakeholder. These values can help an analyst
to choose and adopt a goal from the alternatives of
the goals, to recognize the conflicts among the goals, and to
analyze the impact of requirements changes. Furthermore
the values on a goal graph and its structural characteristics
allow the analyst to estimate the quality of the resulting requirements
specification, such as correctness, unambiguity,
completeness etc. The estimated quality values can suggest
to him which goals should be improved and/or refined. In
addition, we have applied AGORA to a user account system
and assessed it.