How do you quantify a relation between 2 countries? [migrated]
I am trying to create a computer game similar to that of Europa Universalis or Civilization. FYI, those are grand strategy games - you select a country and try to guide it through the years in order to create a world superpower.
In these types of games the existing relations between your country and other countries are crucial for making alliances and signing trade agreements. In most games this relationship is usually a number (integer) between -100 and 100, where 0 means neutral, +100 means excellent, -100 means very bead relations.
My game is set at the present time so I need know how to quantify a relation between any 2 countries.
The first idea that came to my mind was to collect different questionnaire data to find out what people from this country think of that country. However this method doesn't always reflect real relations between governments.