In these days of instant messages, e-mail and cell phones, communication via letters written in longhand is pretty much a lost art.

So it's a bit surprising that a recent survey found that a majority of executives prefer to receive handwritten post-interview thank-you notes, as opposed to e-mail messages, from job candidates they interview.

But the biggest error an applicant can make is not sending any thank-you at all. While only half of applicants send any kind of thank-you, 88 percent of executives said a thank-you note can boost a job seeker's chances of landing the job, according to the survey commissioned by the Accountemps division of Robert Half International. This is just as true for high-level positions in the law department as it is for those at the bottom of the corporate ladder, according to Charles Volkert, executive director of Robert Half Legal, the legal search division.

“Within the corporate environment, among the C-level-type individuals conducting [law department] interviews, a thank-you note is very much appreciated,” Volkert says. “It demonstrates professionalism, initiative and basic courtesy and enhances the chances of the candidate to be hired.”

Volkert recommends sending a quick e-mail thank-you right after the interview, followed by a more formal–though short–handwritten note mailed within 24 hours.

“Don't go overboard,” Volkert adds. “Our feedback from clients is that they like to receive something in the neighborhood of one paragraph.”

Volkert says the letter should express appreciation for the opportunity to interview, reinforce the candidate's interest in the job and restate the value he or she will bring to the organization.

“Beyond that, it gets to be too much,” he says.

If a candidate feels the interview went badly or comes away from the interview realizing the job is not the right fit, he or she should send a note anyway, Volkert says.

“Just because you think it didn't go well doesn't mean the person interviewing you thinks that,” he says. “The thank-you note may tilt the balance in your favor. If you decide you aren't interested in the position, sending a note to the interviewer saying you appreciate their time may pay off down the road when you discover that person is now working at your dream company.”

Following up by telephone may also be appropriate, Volkert says, although never as a substitute for a written thank-you. He recommends asking at the end of the interview what the next steps will be, and asking if the interviewer would like you to follow-up by phone in 48 or 72 hours.

“Set the ground rules as you are closing out the interview,” he says, “and use your best judgment on whether a voice mail message will help.”