Four brands -- Coors' Keystone, A-B/InBev's Busch, and Miller Brewing Co.'s Milwaukee's Best and Icehouse -- demonstrate that longevity does not mean equity. The brands are so besmirched that the breweries should consider retiring them, it says.

The index -- which tracks 30 beer brands -- says that not only is the perception of those brands negative, but it is negative by a long shot.

The Palo Alto, Calif.-based firm says the four don't have a single positive score in the ranking based on surveys of men from January this year until this past Friday. The scores are based on an average of the satisfaction, quality, impression, reputation, value, and recommendation scores. In none of those parameters did any of the four brands score positive numbers, per the firm.

Ted Marzilli, SVP and global managing director for YouGov BrandIndex, says in the two years the firm has been following the category, the four brands at the bottom have stayed at the bottom. "But Keystone and Milwaukee's Best rate much lower than Busch and Icehouse."

He says Busch is relatively popular among 50-plus consumers, lower-income consumers and those in the Midwest. "And when you look at Icehouse it has a niche among African-Americans and is rated more highly by women; its selling points are that it is less bitter, and crisper than others."

Brands that have moved up over time include include Corona, which has gone up modestly, Pacifico and Heineken Light. Marzilli says Budweiser has dropped four or five points recently.

Milwaukee's Best has a minus-20 ranking, followed in ascending order by Keystone, Icehouse and Busch, at minus-10. The industry average in the index is currently around 4.9. At the other end of the spectrum is Samuel Adams, with the highest score -- 26.51 -- of the 30 major beer brands tracked by the Index. Two through five on the list are Heineken, Guinness, Corona and Michelob, with a ranking of 13.12. And Rolling Rock comes in at number 18, with a score of 3.18.

Per the research firm, BrandIndex interviews 5,000 people each weekday from a representative U.S. population sample, constituting some 1.2 million interviews per year. The research firm says respondents are drawn from an online panel of more than a million consumers, with a +/- 2% margin of error.