World Rugby's Player Welfare site has information research, policies and guidelines for medical matters, playing surfaces and equipment used. The guidelines cover both playing and medical aspects of the game.
Men’s and Women's World Rugby Rankings are calculated using a 'Points Exchange' system, where sides gain or lose points based on the match result. Other criteria include the relative strength of each team, the margin of victory, and an allowance for home advantage.Full Explanation
All member countries have a rating, typically between 0 and 100. The top side in the world will normally have a rating above 90. Any match that is not a full international between two member countries does not count at all.
Points are doubled during the World Cup Finals to recognise the importance of this event, but all other international matches, friendly or competitive, are treated the same across the world.