Local search is a complicated beast. Hundreds of factors determine where your hospital ranks in search results—both organic and the local “snack pack”—for any given query. In the competitive healthcare space, those rankings could be the difference between new patients walking through your doors or your competitors’.

Though there are a few exceptions—like April 2015’s so-called Mobilegeddon—Google doesn’t usually come out and tell you what those factors are. That’s why Moz’s annual Local Search Ranking Factors survey is such a valuable resource, with dozens of local SEO experts chiming in on the most important factors.

The #1 ranking factor

The ranking factor identified as the most important in competitive markets is the consistency of structured citations. These references to your hospital’s name, address, and phone number (NAP) can be almost anywhere, but most of them are on local directories, the Internet age’s version of the yellow pages. Consistent data on these directories shows search engines that a business is real and located at the listed address, and search engines reward that consistency in search results.

If your hospital’s citations have inconsistent or out-of-date information, it’s likely that your rankings are suffering as a result. If you’re not sure about their status, just do a quick Google search for your hospital and click on any directories that come up. Directories aggregate information from a number of sources, so chances are there’ll be some inconsistencies if you haven’t optimized them before.

Optimizing citations

1. Claim your Google My Business listing

Google My Business is by far the most important directory you can optimize. The information there is the information that appears in local 7-pack results, so an incorrect address or phone number is particularly damaging. If the data in Google My Business is current, you’ll want to use the same information in other directories. You should also claim Yahoo Local and Bing Local profiles.

2. Submit NAP information to local directories

Some directories, like Yelp and Foursquare, don’t take any research to find. Others need to be unearthed. Start by searching for “[your town] directory” and submit your hospital’s NAP information to them. Moz also lists the top citation sources in dozens of cities across the U.S.

Another way to find citation sources is to see where your competitors are listed. Search for each one and identify their NAP information, then search for it with quotation marks around each piece: “name” “address” “phone” will turn up all directories with that citation information. If they’re working for your competitors, they can work for you too.

3. Submit NAP information to healthcare directories

There are many directories specific to the healthcare space that you need to optimize as well. All those review sites that give you and your physicians headaches? Most of them list your name, address, and phone number. Sites like Healthgrades have high domain authorities and tend to rank highly in search results

4. Update incorrect listings

Whenever you find existing listings with incorrect information, it’s important to update them rather than just submitting new ones. Submitting correct listings won’t make the incorrect ones go away, and you’ll leave Google even more confused than it was before you started. Finding incorrect directory listings is easy—just search for the outdated NAP.