A staffing firm is kind of like Chandler Bing’s job: everyone knows it exists – and that it’s important – but no one can really explain what it is.

In short, recruiters help match the right candidates with the right employers. While many companies have in-house HR departments, staffing and recruiting firms can help when the company’s staffing needs outweigh its recruiting resources. Because they also specialize in sourcing and screening candidates, recruiters can help you find candidates for hard-to-fill positions, even when it seems as though you’ve exhausted every possible resource.

When it comes to utilizing the services of a staffing firm, however, it’s important to first consider your unique staffing needs and recruiting goals, as different staffing and recruiting firms specialize in different things. Below are the three most common types of staffing agencies, and their various areas of expertise.

• Permanent Staffing Agencies: Companies typically use permanent staffing agencies when they want to hire a key person, but do not want to publicize it.  Staffing firms help them search for candidates on the sly. Companies may also leverage staffing firms when other methods of in-house recruiting – job ad placement or employee referrals, for example – have proved insufficient. Recruiters specialize in proactively tracking down and finding qualified candidates.
• Temp-to-Perm Staffing Agencies: Companies typically enlist temp-to-perm staffing agencies when they want to “try out” an employee before taking them on full time. Companies have the luxury of evaluating an employee’s performance and cultural fit before making a final hiring decision.
• Temporary Staffing Agencies: As indicated by CareerBuilder’s most recent Hiring Forecast, more companies are planning to hire temporary and contract workers this year than in previous years. Companies typically use temporary staffing agencies for two reasons: either to fill in for a person who is out of the office for an extended period of time (such as someone on maternity leave); or to supplement staff during peak business periods that demand more help (but not enough to create a full-time posiiton). People who take temp jobs are typically either “career temps” – people who prefer the flexibility temp jobs offer over full-time jobs – or unemployed people who are trying to supplement their income with temporary work.

Looking for a staffing agency to supplement your hiring needs? Ask a colleague or industry peer for a referral. Just as it is with hiring, referrals are often your best source to find quality, trusted professionals. Another option is to start with 2013 Best of Staffing winners, who are recognized among both candidates and clients for providing excellent service in the staffing industry.