Arieh Warshel, one of the 2013 Nobel winners for chemistry, was born in Israel but now lives in the United States. (Robyn Beck/AFP/Getty Images)

For decades, educated and talented Jews from around the world and particularly Europe have migrated to Israel, contributing to an Israeli economic boom that began in the late 1980s and has continued since. In recent years, though, some Israelis have been going the other direction, migrating back to Europe or to the United States. That development has sparked particular concern in Israel about losing some of its highly educated, entrepreneurial citizens – the sort who helped drive the economic miracle.

That anxiety was crystallized for Israel with this year's list of Nobel Prize laureates. The chemistry prize went to three Americans, two of whom were born in Israel but had immigrated to the United States. It's felt like a reversal of the natural order for Israel, which prides itself on attracting other countries' talent. The Nobel was a symbol of that: Of Israel's 11 Nobel laureates, six had been born in other countries before immigrating.

These two chemists, of course, don't definitively prove anything about Israel's trajectory. But this was a live debate in Israel long before the Nobel announcement, which the Associated Press says has "touched a raw nerve about an exodus of scientists, academics and business leaders over the years, and fueled an anguished debate about whether the country can do more to retain its best talent."

A recent study by the Taub Center for Social Policy Studies in Israel found that, since just 2008, a little over one in five faculty members at Israeli universities have left the country to work at American universities. Another study found that one in four Israeli scientists had left the country.

Even more telling than the outflow of these Israelis to the United States, a nation that, after all, does have lots of  money and research universities, is that many are also leaving for a country that Jews fled in droves not so long ago: Germany. The German newspaper Suddeutsche Zeitung says that Israelis are increasingly relocating there; 17,000 live in Berlin alone. That prompted Israeli Finance Minister Yair Lapid to speak out against Israelis "who are prepared to throw away the only homeland the Jews possess simply because life is more comfortable in Berlin."

This sort of reverse brain drain is a very unusual problem. In almost every case, high-skills immigration goes in one direction: from poor countries to rich. There are better opportunities, more support for their work and a higher standard of living in those wealthier nations. For a country to first attract other nation's talented citizens and then lose that talent itself speaks to Israel's unique position.

High-skills immigration to Israel was always unusual in that it was based as much or more on Jewish identity and politics than on economics. Migrants were either driven away from European or Middle Eastern countries by antisemitism or drawn to Israel by a sense of collective purpose. Now, in Europe at least, the antisemitism is eroding or at least is not nearly as threatening as it once was. There's still the draw of Zionism to pull migrants into Israel, but as the movement has become less secular and more explicitly religious, it might be drawing fewer PhDs than it did in decades past.

By all appearances, Israel's brain drain appears to be largely, if not entirely, economic in nature. The AP and Suddeutsche Zeitung reports cite better resources at American and European research universities and higher standards of living. Israel's GDP per capita at purchasing power parity is about on par with Saudi Arabia's and lower than that of most European countries.

Israel knows, then, that it will have to find nontraditional means to keep its most educated and talented workers from leaving for wealthier countries. In the past, that's included some controversial appeals to identity and heritage. In late 2011, Israel's Ministry of Immigrant Absorption ran a series of TV ads warning Israelis against moving abroad or marrying non-Israelis. Here's one, showing an Israeli woman who has moved to the United States but whose boyfriend doesn't understand why she seems sad on Yom HaZikaron, Israel's memorial day. The narrator says at the end, in Hebrew, "They will never understand what it means to be Israeli."

The idea of the ad campaign made sense on paper: Israel wants to keep Israelis from leaving the country, and it's tough to make that case on economic grounds, so the Ministry of Immigrant Absorption tried to do it by appealing to Israelis' sense of identity. But the campaign understandably offended some prominent groups in the Jewish diaspora, whose support is important to Israel; Prime Minister Benjamin Netanyahu's office quickly ordered that the ads be pulled. The whole episode was a reminder of how difficult and sensitive these identity issues can be, even if they seem like a good way to convince Israelis not to move to Manhattan or Munich.