A recent Pew research study found that American Millennials feel they have more control over their success than their European counterparts. In fact, roughly half or more of Millennials in six of the seven European Union nations surveyed by the Pew Research Center last year believe that “success in life is pretty much determined by forces outside our control.” European Millennials were also less likely to believe that hard work would result in change and that they were the masters of their own fate. In contrast, 43 percent of young Americans share this view. Report author Bruce Stokes said that European Millennials “lack a sense of agency” in contrast with American Millennials.

This pessimistic worldview echoes a survey commissioned by Telefonica and the Financial Times in 2013, which reported that nearly three-quarters of Europeans (71 percent) didn't believe they could "make a global difference.”

Why do European Millennials feel so helpless? Economic woes might play a big part. After all, this is a generation that entered the work force at a time when unemployment was at an all-time high in many European countries. And the future doesn’t look much brighter: the International Monetary Fund forecasts Germany will grow a mere 1.3 percent, France by 0.9 percent, and Italy by 0.4 percent in 2015. On the other hand, while things haven’t exactly been sunshine and rainbows in the United States, things are looking up statistically. The Organisation for Economic Co-operation and Development (OECD) projected the U.S. economy would grow steadily in 2015 and 2016 and unemployment rates would continue to decline.

Additionally, American Millennials may feel like they have more control over their lives simply because American society in general values individualism and bootstrapping more than Europeans. Another Pew study conducted in 2008 found that while 58 percent of Americans believe it is more important for everyone to be free to pursue their life’s goals without interference from the state, less than 40 percent of Europeans consider being free from that same interference a high priority.

But the data doesn’t show the entire picture for American Millennials says Carol Graham, the Leo Pasvolsky Senior Fellow at The Brookings Institution.

"While the U.S. outlook is higher than the outlook in most European countries, if you look at the split between the rich and the poor in the U.S. on hard work beliefs, it is very depressing," Graham said. Her research indicates that there is a great divide between optimism among lower income Americans and higher income Americans. In 2007, the top 20 percent of Americans owned 85 percent of the country's wealth, with the bottom 80 percent of the population owning only 15 percent — and that gap has continued to worsen. Graham’s essay “The fragile American Dream: Insights from the Economics of Happiness,” argued that those who were in the top earning percentile tended to have greater life satisfaction and corresponding ability to plan for the future while those in the lower brackets were much less optimistic.

Jean Twenge, author of "Generation Me," says that, while American Millennials possess a greater sense of agency, it may be on the decline. In a paper published in 2011, Twenge and her colleagues found that Millennials were more likely than GenX'ers and Boomers to believe that success is determined by factors outside their control — more in line with their European counterparts than ever before.

In the end, it may be that these measures of agency and optimism don’t actually matter. Studies have shown that just because European Millennials don’t feel that they have much control over their lives doesn’t necessarily mean they aren’t satisfied with them. When asked to place themselves on a ladder where 10 represents the best possible life and zero represents the worst possible life, a median of 56 percent say they currently stand somewhere between the seventh and 10th step. A study conducted by researchers Italy found that over 80 percent of European Millennial respondents felt sure that they will reach their individual target goals.

So why are American Millennials more hopeful than European Millennials? Some of it may be due to the economy and some of it may be due to culture. But it may also be that it doesn’t matter – after all, European Millennials are just as convinced they'll reach their goals.