I thought golden ales were from a different "family" (Munich malt added to give them that golden color); IPAs would be more bitter, hoppier, and higher gravity/abv versions of normal pale ales and would get the sweetness and color from Crystal vs. Munich.
I'll probably have the style police (or style discussion police) run me down for this, but the BJCP guidelines are one place to get guidance on Pale Ale vs. IPA.
If we look at the new BJCP Guidelines for IPAs (Category 14), they're broken down into English IPA (14a), American IPA (14b), and Imperial IPA (A.K.A. "double IPA") (14c). [url:2nqen2j9]http://www.bjcp.org/2008styles/style14.php[/url:2nqen2j9]
And then for Pale Ales we now have two separate categories, one for American Pale Ale and one for English Pale Ales; Category 10 "American Ale", which includes "American Pale Ale", "American Amber Ale", and "American Brown Ale". [url:2nqen2j9]http://www.bjcp.org/2008styles/style10.php[/url:2nqen2j9]
And Category 8 for "English Pale Ales", which includes "Standard/Ordinary Bitter", "Special/Best/Premium Bitter", & "Extra Special/Strong Bigger (English Pale Ale)".
[url:2nqen2j9]http://www.bjcp.org/2008styles/style08.php[/url:2nqen2j9]
So if you're talking about American Pale Ales vs. American IPAs we're looking at:
[b:2nqen2j9]American Pale Ale:[/b:2nqen2j9]
OG: 1.045- 1.060
FG: 1.010 - 1.015
ABV: 4.5% - 6.2%
IBUs: 30-45
SRM: 5-14
[b:2nqen2j9]American IPA[/b:2nqen2j9]
OG: 1.056 - 1.075
FG: 1.010 - 1.018
ABV: 5.5% - 7.5%
IBUs: 40-70
SRM: 6-15
So according to BJCP, the main statistical difference between American Pale Ales and IPAs is the difference in Gravity/ABV on the bottom and top-ends, and the IBUs but obviously there is some overlap. -You should also read through the style descriptions for an understanding of the qualitative differences.
[b:2nqen2j9]English Pale Ale[/b:2nqen2j9]
OG: 1.048 - 1.060
FG: 1.010 - 1.016
ABV: 4.6 - 6.2%
IBUs: 30 - 50
SRM: 6 - 18
[b:2nqen2j9]English IPA[/b:2nqen2j9]
OG: 1.050 - 1.075
FG: 1.010 - 1.018
ABV: 5 - 7.5%
IBU: 40 - 60
SRM: 8 - 14
So... According to the BJCP Guidelines, it's the same basic difference between an English Pale Ale and an English IPA (IPA= higher ABV and more IBUs).
Having said that this is an organization with quite an American slant so take it with a grain of salt, especially for non-American styles. (I'm yet to see an English IPA even remotely close to 7.5%, myself... and if Marston's Old Empire has 40 IBUs I'll be very suprised; it's hop aroma is EXTREMELY light, too.)
I DO, however find most of the QUALITATIVE information on the BJCP site pretty good most of the time.
-Read the taste difference between an American and an English IPA; malt differences, fermentation-derived flavor differences (American Pale Ale doesn't have any), water profile differences, and of course American vs. English hop profiles.
I'm just the messenger trying to answer the question you asked; please don't shoot me!
Adam