The Vagaries of Research - and the Language It Uses

If you're a current or recent student, and if you're interested in advertising or marketing as a career, demographers have a name for you. Actually more than one.

You're probably post-Generation X (those born, it's pretty much agreed, between 1974 and 1980) so you'd be GenY or Ygen or Millennials or iGen or more. Here's a good overview about this confusion - from Wikipedia.

But that's not today's topic. Here are three studies published yesterday or today that deal with your attitudes about the economy that seem to disagree.

First, a Research Brief of a study done under the aegis of Pepsico, in concert with Lipton Tea and Starbucks, is headlined by the Center for Media Research Millennials Anxious Now, Optimistic About Future - and which uses the "born 1980 to 1990" to define "Millennials."
Note well that this research was conducted for the Pepsi Optimism Project by Strategy One, a subsidiary of Edelman Public Relations Worldwide.

Contrast it with these two studies, Fiscal Crises Shape Gen Y's Views Of Marketing and Economy Sours Gen Y On Marketing, both conducted by Media Logic.

I suspect that there is a difference in methodology between Strategy One and Media Logic. Or is it simply how they present the data?

What do you think it would be? How would you confirm this suspicion?