Your donation can change someone's life.
For a few thousand dollars or so, you can save or improve someone's life in the developing world. This claim isn't a normal "marketing pitch" you read in direct mail solicitations—it's the result that outstanding charities achieve. For more, see:
The wrong donation can accomplish nothing.
Charities that demonstrably change lives are the exception, not the rule. Why? Fundraisers often rely on social connections or emotional pleas, and almost never make fact-based demonstrations of programs' effectiveness. This means that lots of charities raise money and run programs without ever demonstrating that their programs actually work. Why should charities have to demonstrate that their programs work?
Experts, governments and foundations have tried (and often failed) for decades to solve many of the same problems charities are working on today. This means that many charities may not be accomplishing anything at all. For more, see:
Your dollar goes further overseas.
Ultimately, there's no "right" answer to the question of which cause you should support. As you consider that decision, it's worth recognizing that the impact you can have with your donation varies greatly between causes. If you focus on education in New York City, it costs over $100,000 to educate a student throughout 12 years of school. When supporting international aid, you can save a person's life for a few thousand dollars or so.1 That doesn't mean you should necessarily support international aid, but, just like any time you spend your money, it's important to know what you're getting. For more, see: