Complex sentence: The Australian Tertiary Admission Rank (ATAR) is the primary criterion for entry into most undergraduate-entry university programs in Australia, it was gradually introduced during 2009 and 2010 to replace the Universities Admission Index, Equivalent National Tertiary Entrance Rank and Tertiary Entrance Rank.
Split into simpler sentences: The Australian Tertiary Admission Rank (ATAR) is the primary criterion for entry into most undergraduate-entry university programs in Australia. It was gradually introduced during 2009 and 2010 to replace the Universities Admission Index, Equivalent National Tertiary Entrance Rank and Tertiary Entrance Rank.