Lots of health data comes from surveys. Here are some issues to consider when looking at survey or estimated data:
(Adopted from information on the UCSF Family Health Outcomes Project web site, and from How to “QuantCrit:” Practices and Questions for Education Data Researchers and Users)
Reliable data collection: relatively free from "measurement error."
Validity refers to how well a measure assesses what it claims to measure
(Adopted from Chapter 3, Conducting research literature reviews: from the Internet to paper, by Arlene Fink; Sage, 2010.)