It is not necessary to send a thank-you letter after a screening interview with a large firm as part of the fall on-campus interview program. Other employers, however, particularly smaller law firms, do sometimes expect you to send a thank you note after a screening interview -- so we recommend that you send one, addressing it to the lawyer who conducted the interview. You should always send a thank-you letter after a call-back interview, no matter the employer's size. A thank-you note will only hurt your chances of receiving an offer if it is poorly written or contains typos or grammatical errors.
The thank-you letter after a call-back interview should be addressed to the person who was most responsible for coordinating your interview (e.g., the recruiting coordinator, hiring partner, director of the organization). If you met with multiple people, be sure to ask the addressee to thank the others for taking the time to meet with you. You may also choose to write separate letters to each of the people with whom you met, but this is not required. If you do write separate letters, try to individualize each of them, as they all eventually may be forwarded to your file.
You should try to mail your thank-you letter within 48 hours of your interview. If the letter is typed, you should use the same bond paper you used for your resume. You may also send a handwritten note with a professional looking thank you card. Lastly, you could e-mail your thank-you letter (in fact, some employers may expressly state a preference for e-mail correspondence). However, be aware that this method of expressing your thanks is not without risk, as the recipient might be offended by its (unintentional) informality. If there is any question regarding a recipient's reaction to an e-mail thank-you, we strongly advise the more formal option of sending a typed letter via regular mail.
The letter should be no more than a couple of brief paragraphs. Thank the person for meeting with you and reiterate your interest in the firm/organization. Try to mention something specific you learned or discussed in your interview. For example, you can reiterate briefly how your skills and experience would be a good fit for the firm/organization. You should also offer to provide any further information that may assist in the hiring decision process.
Finally, be sure that your letter is error and typo-free. If possible, have a friend or family member proofread it before you send it off. The worst thing you can do is misspell the name of the person to whom you are writing or the name of the firm/organization. In order to ensure proper spelling, we recommend that you check resources such as Martindale-Hubbell or the firm/organization's web site. Better yet, ask for a business card from each person with whom you meet.