When researchers draw conclusions about something on the basis of regression analyses, in general, how strong might their conclusions be and how likely might they be affected by bias?
For example, in relation to a standard hierarchy of evidence, such as this one here Article Options for basing Dietary Reference Intakes (DRIs) on chron...
my feeling is that regressions sit around the middle of the pyramid by cross-sectional studies.
Does anyone have any opinions?