“Secular stagnation” is an emerging topic in
macroeconomics. It is most often
associated with Lawrence Summers, who wrote a recent blog post on the subject: http://www.washingtonpost.com/opinions/lawrence-summers-supply-issues-could-hamper-the-us-economy/2014/09/07/274ce00c-352f-11e4-9e92-0899b306bbea_story.html.
Summers’ post notes that his conceptualization of secular
stagnation looked mostly at the demand side of the macroeconomy (for example,
the Zero Lower Bound on interest rates), but that others – he mentions Robert
Gordon – emphasize supply side considerations, like an aging population and the
end of large increases in women’s labor force participation.