Mathematics of the Pop Charts

Extract

We distinguish between a level on a sequence of charts (e.g. top level or 5th level) and a place on a single chart (e.g. 5th place on the 22nd week). A song occupies a place by halting there prior to a continued rise or fall of its path, or by stopping there if that place is at the highest level attained. A song which passes to a level higher (or lower) than level p without halting there bye-passes level p. The upward path of a song terminates at the first stopping place and the downward path commences at the last stopping place. Note : Level No. 1 is the lowest level and level P is the uppermost one. This is contrary to popular usage but makes the mathematics more conventional.