In statistics (and some other fields, such as medicine, I believe), the best available benchmark under reasonable conditions is sometimes referred to as "the gold standard". This phrase is also used colloquially to mean an ideal against which others are compared – google gives its definition as "the best, most reliable, or most prestigious thing of its type".
I can think of two plausible origins of this phrase. "The gold standard" seems at first to mean the standard (for comparison) that is golden (i.e. the best). But I could also see it having emerged from analogy to the literal gold standard, i.e., "the system by which the value of a currency was defined in terms of gold, for which the currency could be exchanged".
What is the true origin of this phrase?
The wikipedia article clearly believes it's the former:
The phrase is therefore ambiguous and its meaning should be deduced from the context in which it appears. Part of the ambiguity stems from its usage in economics, where "gold" does not imply "best" but is merely one of many possible standards.
But there are no sources for this interpretation cited, and not even any discussion on the talk page about it, so I'm not sure I can take this as more than just one person's opinion.
EDIT: I can (and have) come up with plausible justifications for both interpretations. I'm asking this question in the hopes of a more definitive resolution to the question, so I'd prefer (if possible) answers that could shed some light on the history or origin of the phrase being used as described, or offer sources that do the same.
Best Answer
I think it refers to the economic monetary concept of "gold standard" which, being based on physical gold was considered reliable and popular given the supposed advantages that gold has over other commodities. Since the phrase "gold standard" refers to the actual exchange of a currency for gold, guaranteeing its value, any "gold standard" item has thus been used to refer to a benchmark of the highest quality.
(Wikipedia)