For the purposes of classification for Nielsen ratings as the show is split between primetime and late night, it is officially classed into four separate "parts" to demarcate numbers between the lower-rated start and end of the special, and the higher-rated countdown portion. The first two hours are referred to as "Part I", with the 10:00 p.m. hour considered "Part II". The actual Times Square countdown programming portion starting at 11:30 p.m. ET/PT up to approximately 12:10 a.m. ET/PT is classed as "Part III", followed by the heavily taped performance "Part IV" (outside the 1 a.m. ET New Orleans/Central countdown) leading up to the special's end.