McD's millennial problem: Is new campaign working?

McDonald's is pinning its domestic turnaround hopes in part on a new campaign to dispel misconceptions about its food. Although the new effort appears to be working with millennials, the fast-food chain has a deep hole to dig itself out of with this key dining group.

Since the McDonald's transparency videos answering questions about its food quality went live Oct. 13, consumer perception does appear to be shifting slightly, according to data compiled for CNBC by YouGov BrandIndex, a daily brand consumer perception research service.

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"The major movement since the metrics has been with millennials and to a lesser extent with moms," said YouGov BrandIndex CEO Ted Marzilli in an email. "Both of these groups have seen an uptick in quality perception and purchase consideration. Fast-food eaters in general, however, have shown little movement in their quality scores or likelihood to purchase."

From Oct. 13 to Oct. 20, millennials' quality score for McDonald's rose to -21.4, from -32.2. While this shows improvement, it's still markedly in negative territory, which indicates these diners have a poor overall impression of the chain. It's also much more negative than the average fast-food diner's perception of McDonald's quality, the report found. Fast-food eaters' quality perception rose to 0, from -3.5.

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The firm's quality score is determined by asking respondents "Does the chain represent good quality or poor quality?" and having them score a brand from -100 to 100 with zero equaling positive and negative feedback.

The respondents consisted of 1,000 millennials, 700 moms, and more than 4,300 fast-food eaters.

A separate Nielsen report found McDonald's failed to crack the top five quick-service restaurants for millennials, RBC analysts noted earlier this year. Chipotle Mexican Grill, which reported a surge in comparable store sales Monday, took home the top spot instead.

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Meanwhile, McDonald's has struggled to deliver positive sales at restaurants open at least 13 months. In September, McDonald's reported its worst monthly comparable sales decreases in the U.S. and Europe since early 2003.

On the McDonald's earnings call, CEO Don Thompson pointed to a broader decline of millennial dining at quick-service restaurants—rather than an issue that's affecting merely McDonald's.

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YouGov BrandIndex also asked people whether they would consider dining at McDonald's the next time they were in the market for fast food to determine purchase consideration.

This metric also indicating a poor impression of McDonald's among milllennials than fast-food eaters. Still, both measures have risen since the videos launched. The purchase index for millennials now stands at 34.3 percent, up from 29.5 percent while the fast-food eater index has risen to 44 percent from 40.2 percent .

While these scores remain higher than the fast-food industry average, they've shown a long, slow decline, Marzilli said.

He added that he was surprised to see any positive movement in the data at all for millennials since it's only been a week into a new effort to address an issue that's been building for years.

Still, he cautioned it's too early to call the campaign a success or failure.

"McDonald's current perception with consumers has developed over years (decades really), so one campaign is not likely to change that in a week," he wrote. "McDonald's as one of the biggest players in the QSR space, has historically taken the brunt of industry criticism."