The +/- columns (ranking difference and points difference) are based on the current and previous week's rankings. The ranking difference is how many ranking spots that player moved since last week' rankings. Similarly, the points difference is how many points a player gained or lost in the last week. NR in "RANK DIFF" column indicates that player was not ranked last week. There is also a possibility that if there is a difference in spelling in that player's name, it will also register as NR.