Interesting Question. In my experience, a strong, direct correlation has yet to be made between brand strength and business performance. I think that may be cutting out some important middlemen. Business performance translates into profit, and profit enables marketing. Marketing, along with company-wide objectives (or "vision") creates and maintains the brand, and therefore determines it's strength. This determination is based on it's overall projected effect on a user/customer's recognition, recollection, emotional impact, and trust
The effectiveness - and therefore value - of a brand, from a customer standpoint (and, in turn, a financial one) depends on the ability of a company to instill the above values in the customer. If successful, that company earns more than a purchase, it enters a relationship. If that company delivers on the implied promise hidden beneath the brand, the relationship will be fruitful.
In Short: The higher the repeat-business numbers, the stronger the brand.
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a few resources i liked:
Route to a brand's best strategy: new findings challenge the belief that market share alone correlates with profitability. Bain & Company's analysis of 200 brands shows that products at the high end stand to earn considerably more with a smaller share of the overall product category.(Sounding Board)
People, Planet Profit The Value of Corporate Social Responsibility - People generally want to align themselves with companies they admire and respect...the glare of the media is aimed directly at corporations nowadays; any small glitch in a company’s reputation could dramatically impact their revenues both long- and short-term.