I keep a checklist that helps me decide whether or not to make an investment.

After all, I want to be confident that the investment has what it takes to become part of my portfolio.

One of the main criteria on that checklist is diversification: Will the investment help diversify my portfolio?

That’s a tricky question: Financial markets are now deeply entwined in ways that they never were before.

But our notions are still outdated – some investments that we think provide diversification actually don’t and, in fact, behave quite similarly to one another.

True diversification means owning assets that wont rise and fall together. And because of the brave new world of highly connected markets, that can be difficult to achieve.

Fortunately, with ETFs, we can diversify much more simply than if we were left to our own devices.

The following ETFs are excellent vehicles for diversification. Here’s a quick look…

WisdomTree Emerging Markets Local Debt Fund (ELD )

As the name suggests, the WisdomTree Emerging Markets Local Debt Fund invests in debt issued in emerging market countries.

For investors seeking income and diversification, it offers a healthy start.

Not only does the fund boast a 3.81% yield, but it’s very unlikely that it overlaps with the other investments in your portfolio.

The fund invests in places like Mexico, Malaysia, Turkey and South Korea – a total of 15 different countries in all.

What’s more, its emerging market debt investment moves independently from other major asset classes, adding further diversification.

Granted, the fund is rather new, but it’s performed well to date. Launched in August of 2010, it’s up a cumulative 16.95% through March 31, 2013.

CurrencyShares Australian Dollar Trust (FXA )

Another method used to diversify your portfolio is investing in foreign currencies.

You could go to a bank and exchange your dollars for a different currency, or you could open an online foreign exchange account.

But many investors find these to be inefficient or cumbersome options.

An easier way to invest in foreign currency is through an ETF like the CurrencyShares Australian Dollar Trust.

The fund invests 100% in Australian dollars and has a dividend yield of 2.59%.

But it doesn’t just have dividends on its side – the fund also delivers significant capital gains. In fact, over the last three years, it has an average annual return of nearly 8%.

Of course, investing in FXA means you have to know whats going on in Australia. Australias central bank – like central banks everywhere – may or may not decide to change monetary policy, causing the currency to rise or fall, and FXA to do the same.

Notably, CurrencyShares also has funds dedicated to many other currencies. But, in any case, keeping on top of global and national monetary shifts will remain a necessity regardless of the currency invested in.

WisdomTree Emerging Markets Small Cap Dividend Fund (DFE )

Last, but not least, the WisdomTree Emerging Markets Small Cap Dividend Fund invests in – you guessed it – small-cap stocks with a focus on dividends. And, most importantly, it doesn’t concentrate on the big four emerging markets (Brazil, Russia, India and China).

Brazil and China are in the top 10 countries – Brazil is the fifth largest holding and China is the tenth – but the fund is also invested in less popular emerging markets like Taiwan, Thailand, South Africa and Chile.

The fund sports a yield of 2.82% and it continues to perform well, as share prices have risen from $20.00 in March 2009 to more than $50.00 today.

Further, ELD’s expense ratio of 0.58% is in line with ETF averages, so you’re not overpaying for the management costs of the fund.

Bottom line: Maintaining a diverse portfolio is no easy task. And although each of these funds brings something unique to the table, they have one thing in common: They’ll help you accomplish exactly that.