BOSTON ( TheStreet) -- Smart consumers put as much research into picking good charities as they do good stocks -- lest their hard-earned cash go more toward a nonprofit's office space or payroll than to actual good works. "There's not a whole lot of regulation," says Sandra Miniutti of CharityNavigator.org, a website that rates U.S. nonprofits. "State attorneys general have tried to put in place some sort of bottom-line amount that charities have to spend on good deeds , but the Supreme Court has shot that down under freedom of speech rules ." To help fill the accountability void, CharityNavigator analyzes financial disclosures that some 6,000 nonprofits file annually with the Internal Revenue Service, determining how much each group spends on good works and how much covers overhead. The website also grades charities on 17 "accountability and transparency" criteria, from the use of independent auditors to disclosing top executives' pay. Here's a look at five nonprofits that get CharityNavigator's highest marks among groups that rely strictly on private donations rather than government grants or income from such things as museum ticket sales. Miniutti says the charities below are all good choices for holiday donations because they need private donations to survive -- and because they all get top marks for financial performance. All five spend roughly 90% of donations on good works and only about 10% on overhead, surpassing a 75%-to-25% ratio that's considered standard for well-run charities. "Donors can be highly confident that these charities make efficient use of their donations," Miniutti says.