Because we're in an urban environment - we can't guarantee that setting particular filters in the ad algorithm will be accurate. Our university has a total enrollment of about 16,000 FTE spread across the undergraduate, graduate and med/law school units. While I'm not aware of the exact numbers, it's safe to say most of our undergrads live near the main campus, and most of our graduates do not. That means I'm estimating about 10,000 students live within a mile of our main campus. However, if you track the total population in the two zip codes the campus covers - that's over 100,000 residents! That means our students are only 10% of the population within one mile of our campus. There are two branches of the Chicago Public Library within that radius, a private organization called Gerber Hart Library, and a fetish museum that all show up in a Google search for "library" near 60626. On top of that - our library is incorrectly labeled on Google maps! Post grads also tend to stay in the area for a while, so even using "Loyola University Chicago" and within 1 mile of our location in our Facebook advertising requirements can still hit the wrong Facebook accounts. Supposedly $50 of Facebook ads can make 100,000 impressions - that means everyone that lives in Rogers Park and Edgewater could see our advertisement once - rather than each Loyola student seeing it ten times.
It's important to seek out good advice from seasoned professionals, but take some time to ask these professionals about your particular circumstances, and see if there's a method to alter your efforts to improve your results. It's also important to not let these professionals push you around and bully you into a strategy that won't work for your library. Lastly - many library administrators or directors are starting to support the social media marketing bandwagon; be sure they are as informed as possible before making and strategic decisions regarding Facebook (or other Social Media) advertisements! It's important to curb expectations, consider your individual circumstances, and aim for a maximum impact campaign.
I'll continue the Urban Library series in future posts discussing some of the other topics mentioned above.