What counts as a good run rate depends on the nature of the pitch, the type of match and the level of the game.
A Test match held over five days typically has a lower run rate than a limited-overs game, because batsmen adopt a more cautious approach.
In recent years, the average Test run rate has been between 3 and 3.5 runs per over, sometimes even lower[2] whereas in limited overs cricket the batsmen must adopt a more gung-ho approach in order to achieve the necessary score to win.
Fielding restriction rules, now known as Powerplays, are used by the cricket authorities to encourage faster scoring in the earlier part of the innings.
It can also be used to separate teams in a league table with the same win–loss record, though that is usually done by the net run rate method.