Diversification and asset allocation are twin building blocks of a solid investment foundation. Though the concepts are closely related, understanding each rather than just mixing them together can help you make the most of both. Consider these basics:

Diversification. This is the method of spreading out investment dollars among different categories, or “baskets,” in order to reduce your overall risk. For instance, even if you’re 99% sure that a particular stock is about to take off, you don’t want to invest your life’s savings in only one stock. There’s still a chance it will tank, leaving you in a financial hole you may never get out of. Similarly, you want to avoid putting all of your investment dollars in a single basket—stocks, bonds, or copper, say—no matter how fundamentally sound the category may seem.

Diversification may work because different kinds of investments tend to rise and fall at different times. If you hold a variety of investments, some may do well when others stumble. Additional benefits can come from diversifying within categories—by spreading your stock investments over many industries and also holding shares in foreign companies. By the same token, you’ll probably want to own different kinds of bonds with various maturities. Yet while broad diversification may help your investments weather a worst-case scenario, it can’t protect you from losses, especially in a declining market.

Asset Allocation. Closely related to diversification, asset allocation goes a few steps further. Here, you seek to divide your holdings among major investment categories based on a set percentage for each category. Because each group has a unique combination of historical risks and returns, it’s expected that each also will perform differently in the future.

This is diversification with a little more science. Because it’s likely that if one category loses value, another may be on the upswing while a third holds steady, devoting an appropriate percentage of your portfolio to each can keep your portfolio in balance.

Yet there’s also a lot of art involved in asset allocation. Choosing the best percentages for your circumstances requires looking at several variables, such as your objectives, age, health status, amount of assets, and tolerance for risk. And because your goals are likely to shift, allocations need to be reevaluated and adjusted periodically. Typically, your choices will become more conservative as you near or reach retirement.

Asset allocation provides a rigorous method for achieving diversification in your investment portfolio. Having the two ideas working smoothly together can help you move closer to your financial goals.