Job advertisements rarely find all the people you're looking to attract.
One major reason is that only about 12 percent of potential job candidates are actively looking at job boards -- and even fewer will see your individual ad anyway.
Of those 12 percent, the job title is the first thing your potential candidates see. It's also the only chance you have to convince job seekers to click.
Much like judging a book by its cover (or title), people click on a job posting because of its potential appeal. Pick a title that doesn't make sense in the mind of those candidates, and they'll ignore it (except for the most desperate, and you probably won't want to attract them anyway).
Even if you have what you think is a seemingly standard title, you probably don't -- the market is far more diverse than you anticipate.
And the market is ultimately where advertising fails. Like so many other aspects of hiring, a failure to use the right job titles is a failure to consider the outside market, instead of your own internal perspective and internal considerations. Do you consider how an externally advertised title might be different than your internal title?