Wikipedia:Articles for deletion/Envelope model
I am not a statistician, and haven't had the chance to do a detailed .  However I understand it, the topic of the article seems like a fairly standard thing that one would like to do in statistics, namely project onto the principal components of a data set that satisfy some (linear) constraints.  The article itself seems well-organized and clearly written.  I (a non-specialist) could understand the first few sections, but not so much the later sections.  I think that is to be expected for articles on technical topics.  It could use an introduction written one or two levels down from where it is now.  I also think examples should be clarifying for typical readers, rather than included as proof-of-concept for more sophisticated readers.  But Wikipedia is not paper, and there is no reason an article cannot have both types of examples
— User:Sławomir, 11:39, 24 April 2017 (UTC)
Stance: keep
Cited policy: WP:BEFORE (Wikipedia:Articles for deletion)