Data and Evidence
Data is not the plural of anecdote
"Data is not the plural of anecdote"
(often used misquote of the Ray Wolfinger aphorism)
"The plural of anecdote is data"
- Ray Wolfinger
Wolfinger’s formulation makes sense: Data does not have a virgin birth. It comes to us from somewhere. Someone set up a procedure to collect and record it. Sometimes this person is a scientist, but she also could be a journalist.
Absence of evidence
"Absence of evidence is not evidence of absence."
In Sagan's words, the expression is a critique of the "impatience with ambiguity" exhibited by appeals to ignorance. Despite what the expression may seem to imply, a lack of evidence can be informative: where evidence would be expected if a claim were true, its absence counts against the claim (see Argument from Silence).
Extraordinary claims require extraordinary evidence aka (Sagan's standard)
"Extraordinary claims require extraordinary evidence”
"the weight of evidence for an extraordinary claim must be proportioned to its strangeness"
- Gillispie et al., 1999
See Sagan Standard and Burden of proof.