Every reporter has been there: An editor assigns a story on an unfamiliar topic and there’s a mad-dash to find a source who can provide crucial information.

But how to find a reputable, reliable source?

In 2007, a public relations professional named Peter Shankman created a database that would put reporters in touch with sources and help experts share their knowledge with credible media outlets.

Now that database, Help A Reporter Out, or HARO, has more than 800,000 people who receive emails three times a day, plus access to specialized topic and keyword-based newsletters.

“By and large, it’s still a free membership platform,” said Kristen Sala, a senior director of U.S. media research. “People love that, both sources and journalists alike.”

HARO is now under the umbrella of Cision and continues to grow.

“We connect journalists seeking expertise with sources that have relevant expertise,” said Allison Richard, one of HARO’s managers. “We send about 200 queries from journalists a day, maybe closer to 300. Each day we send three emails – at 5:35 a.m., 12: 35 p.m. and 5:35 p.m., all Eastern time, Monday through Friday.”

Journalists looking for a source fill out a form detailing the topic, with as much information about the questions to be answered as possible, along with the deadline.

“If you’re submitting a query for a story about a medical insurance policy, you might select business and finance as a category for your query, or health care. When we send daily alerts in the business and finance edition, that query will be included in that.  We leave in the hands of journalists the ability to code the query accordingly,” Richard saids.

It’s also of the utmost importance to be very clear about the deadline for the story, to avoid a situation in which the reporter is up against a wall waiting for information when the story needs to be published.

There are also some guiding rules to protect both reporters and sources. If a source turns out to be unhelpful or doesn’t come through with the promised information, the reporter can make note of that. Alternately, reporters must work for a publication that has been around for at least one month – whether print, online, broadcast, etc. – to ensure the source’s time and information will be published as intended.

“It’s a win-win,” Sala says. “You’re a source because you’re looking to get your brand or your name mentioned. If an outlet hasn’t been established for very long, there’s a chance that outlet could go under or a story doesn’t get published. It’s a protection of our sources.”