<p>You need two teacher recs. What you’re referring to – whether it’s from a Yale professor or your mayor or governor – is a supplemental rec. A supplemental rec is useful only if the person writing it knows you and can say something substantive about your achievements/accomplishments beyond what your teachers have said in their recs. Typical supplemental recs come from an athletic or debate coach, a private music teacher, or a member of the clergy. So if you’ve worked on a project with the Yale professor, s/he might be able to provide an excellent supplemental rec. If s/he is a family friend and is simply going to attest that you come from a fine family or that you’re a fine person, then no. </p>
<p>The Yale admissions website is your friend. It will provide the answers to many of your questions. [Welcome</a> to Yale College, Office of Undergraduate Admissions](<a href=“Home | Yale College Undergraduate Admissions”>Home | Yale College Undergraduate Admissions)</p>