YouGov, which measures consumers’ perception of various brands, is reporting that brand perception of Yahoo is down considerably over the past year, and particularly since the whole NSA PRISM scandal broke.

“One year after Marissa Mayer assumed the CEO title at Yahoo, the company’s stock price is approximately 60% higher than when she started, but the company’s brand health measurements, based on consumer feedback, have moved in the opposite direction,” a spokesperson for YouGov tells WebProNews, citing the firm’s YouGov BrandIndex.

“Revelations in early June that the National Security Administration collected massive amounts of consumer data from the top Internet companies seems to have been particularly damaging to Yahoo’s consumer perception, along with that of its rivals,” the spokesperson says. “The group’s brand health scores have just begun to rebound, although they still nowhere near the levels where they were before the news broke.”

It’s worth noting that Yahoo actually earned some points with some people with regards to the whole PRISM thing. In fact, the EFF is giving the company special recognition for tis “fight for users in secret court”.

“Yahoo’s gradual descent has also been closing the consumer perception gap between itself and an average of its competitors, such as MSN and Bing,” the spokesperson adds. “While Yahoo is still running ahead of the average of its rivals’ scores, its lead is the smallest it’s been in four years.”

NSA scandal aside, Yahoo has clearly been undergoing significant changes over the past year with Mayer taking over. While change and new CEOs are hardly anything new for the company, things appear to be moving in the right direction on the business side of things, and the stock prices are evidence of that.

Part of all of the change has been a host of redesigns to popular products. That can affect brand perception, and probably for the negative, because pretty much all major redesigns come with an abundance of criticism. For Yahoo, the redesign of Yahoo Mail in particular has sparked a great deal of negative reaction. Like with most redesigns, however, the negative reactions will fade away in time, and it’s hard to say how much positive impact the same redesign has had, because people who are content don’t tend to be as vocal as those who aren’t.

Another major part of the change at Yahoo is the number of acquisitions the company has been making. Frankly, I’ve lost count, but it’s a lot, and with all these companies come users who aren’t eager to have control over their favorite products fall into the hands of a corporate giant like Yahoo. See Tumblr. While Yahoo is trying not to “screw up” Tumblr, some of the products it acquires simply get shut down. That’s not going to favor brand perception among happy users who don’t wish to see said products go.

These are all factors that could have a direct impact on brand perception, and the fact that it’s rebounding for Yahoo in spite of all of this, is probably a great sign for the company. As is the stock price.

More on the subject from YouGov here.