id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
34325	PercentRank confusion	dennisvang	nobody	"The [https://docs.djangoproject.com/en/4.1/ref/models/database-functions/#percentrank documentation for the PercentRank window function] says:

  Computes the '''''percentile rank''''' of the rows in the frame clause. This computation is equivalent to evaluating:
  {{{
  (rank - 1) / (total rows - 1)
  }}}

(my emphasis)

However, I'm not so sure ""[https://en.wikipedia.org/w/index.php?title=Percentile&oldid=1114275310 percentile] rank"" is the correct term. 

If you look up the (statistical) term ""percentile rank"" online, you'll find various definitions, [https://en.wikipedia.org/w/index.php?title=Percentile_rank&oldid=1136815121 ranging from]

{{{
(CF - 0.5 * F) / N
}}}

  where CF—the cumulative frequency—is the count of all scores less than or equal to the score of interest, F is the frequency for the score of interest, and N is the number of scores in the distribution.

[https://www.geo.fu-berlin.de/en/v/soga/Basics-of-statistics/Descriptive-Statistics/Measures-of-Position/Percentiles-and-Percentile-Rank/index.html to something like]

{{{
<number of values less than the score of interest> / <total number of values in the data set>
}}}

However, none exactly matches the definition in the Django docs.

Note also that the documentation for the `percent_rank` function in the [https://www.sqlite.org/windowfunctions.html#built_in_window_functions SQLite] and [https://www.postgresql.org/docs/15/functions-window.html PostgreSQL] database backends does '''not''' mention ""percentile rank"". Instead, they use the term ""relative rank."" 

To prevent confusion, wouldn't it be better to use the same terminology as the database backends?
"	Uncategorized	new	Documentation	4.1	Normal				Unreviewed	0	0	0	0	0	0