Human resources management is more art than science, and most HR managers wouldn't have it any other way. But there may be days when you wish you could just plug numbers into an accounting formula to get an idea of a job applicant's potential value to the company. Happily, it turns out there are some ways to "quantify" a candidate's potential contribution. Here are some things to consider:

• Equity investment. Does the candidate already have the skills needed for the job, or will he or she require training? Although all new hires will need orientation, some will be productive sooner than others. How do you determine which ones are likely to offer a quick payback? Ask open-ended questions during the interview about their knowledge and skills. Request proof of their accomplishments, such as certifications, certificates of completion, or degrees from accredited schools and organizations. If the job requires operating a forklift or driving a truck, have the candidate take a test drive. That's not to suggest you should always give preference to experienced people over entry-level applicants. The idea is to get a sense of how much the company will have to invest in training the person before it begins to see a return.
• Fair market value. What's the going rate in your area for someone with a given candidate's training, skills, and experience? Keep in mind, however, that determining the going rate isn't always as straightforward as it might seem. Before you can make valid wage-scale comparisons, you have to know exactly what those other companies are paying for. Say that you find that the outfit across town offers $2 more an hour for a forklift operator than you do. If you do a little research, you might discover that your cross-town rival requires that applicants have a license, while your company covers the cost of training as well as the licensing fee.
• Estimated duration. Short of a crystal ball, there's no way to know how long someone will stay with your company. But his/her resume may provide some clues. For example, a string of short stints may indicate that the candidate has a bit of wanderlust in his or her DNA. If that's the case, be careful. He or she may not stick around long enough to make hiring him or her worthwhile.
• Goodwill. Don't overlook the applicant's potential to generate goodwill for your company. This isn't something to think about only when hiring for sales and marketing slots. Most employees will have contact with the outside world at some point or other. Truck drivers, for instance, will interact with loading dock personnel at your client companies. Because your employees are the public face of your company, you'll want to be sure that they're making the right impression. During the interview, take note of the applicant's social skills. Be alert for a tendency to blame others, to complain, or to try to create a bond through negativity.
• Intellectual property. What does this applicant have to offer beyond simply filling a chair? Does he/she have other skills or abilities that will enhance the department's performance? A supervisor who coaches his son's Little League team on weekends might be able to put those same skills to good use running the department's mentoring program.
• Revenue generation. Again, this isn't just something to look for when hiring people for sales and marketing positions. Every employee has the potential to generate revenue for the company—or if not generate revenue, at least the capability to keep costs and expenses in check.

One other note: When it's your turn to be the candidate—instead of the hirer—keep these "valuation" components in mind. They're a great way to convince your interviewer how valuable you'd be to the company.