====== Survey study ======

A method for collecting quantitative information about items in a population
Opinion poll, an assessment of public opinion.

A nationwide survey confirmed sex differences in the association between various self-reported [[sleep disorder]] and [[cognitive decline]] in people aged 65 and older
((Chiu HY, Lai FC, Chen PY, Tsai PS. Differences Between Men and Women Aged 65
and Older in the Relationship Between Self-Reported Sleep and Cognitive
Impairment: A Nationwide Survey in Taiwan. J Am Geriatr Soc. 2016 Sep 14. doi:
10.1111/jgs.14316. [Epub ahead of print] PubMed PMID: 27627762.
)).

===== Online survey =====

[[Online survey]].