"Your letters could change my life." These words were sent to me by a Chinese student whose lifelong dream is to study in America. I met her in September 2007, just a week after arriving as a visiting professor at Tsinghua University's School of Journalism and Communication. She attended a lunch where I was speaking. We exchanged some pleasantries. She e-mailed a follow-up greeting and wished me a pleasant Mid-Autumn Festival. About a month later she invited me to have dinner at a restaurant near the Tsinghua campus in Haidian. She gave me a bag of shrimp from her hometown near Qingdao.

Our dinner conversation revolved around her recent job at a radio station and her study for the GRE and her lifelong dream for further study in America. She looked anxious. By the time we moved from the restaurant to Starbucks, she very delicately broached the topic of a letter of recommendation.

I was a bit stunned by the request given our superficial knowledge of one another. "Your letters could change my life," she later wrote in one e-mail with attached resume and draft letter of recommendation. "However intelligent or hard working I am, if I have no one to recommend me, no one could know me and give me a chance."

Was I even ready for such a life-altering commitment? I decided to be as honest with her as I could, even though it wouldn't be what she wanted to hear. First, I told her that she needs to secure letters from people who have supervised her work or know how she performs in research and writing. I could only write a generic "To Whom It May Concern" and explain that I had met this student on two occasions and that we were able to converse at an advanced intermediate level in English. I would also be willing to add that she is highly motivated to succeed in her studies in America, but then who isn't?

I'm not so sure such a letter would change anyone's life.

Letters of recommendation are serious business for U.S. professors. Each professor is a little different but we all have rules of engagement. My rules are written out in my course syllabus. With few exceptions, I will not write a letter of recommendation for anyone who has not performed at the highest level in my class, and that usually translates into a solid "A" final grade. I prefer to know a student for two semesters, if possible, but since I teach at one of the largest state universities in the world (California State University), it's not always possible to have repeat customers. More often I serve as a job reference.

I remained perplexed as to why I was asked by several Chinese students to write letters of recommendation. Finally one student explained that in China, such letters of recommendation are not the usual practice. She said that many Chinese professors don't have a clear understanding of how much these letters mean to Chinese students. They respond by telling the students to write up something that they can simply sign. Or they don't respond at all. If students draft their own letters (which I often have my students do), then they take a risk of praising their accomplishments too much. I look over student-drafted letters with a fine toothcomb in order to avoid this tendency to over-praise. The worry is that too many student-generated letters may lead to a flood that start to sound suspiciously the same--in the top 1-3 percent among their peers, for instance.

What Chinese students need are accurate measures of their work. Professors here need to be accountable to these students. Universities need to instruct students in how to go about making the appropriate request. It's a complicated dance that requires balance and mutual respect.

If students expect that one letter from an American professor is going to "Open Sesame" an American graduate school's door, then they are naïve. Some students think that I have enormous connections to get them admitted to their dream school. One student said that the U.S. professor's letter of recommendation enjoys higher credibility than one from a Chinese professor. I can't understand why a letter from a Chinese professor who knows that student's work would not be just as credible as one from an American visiting professor who doesn't know that student's work. "Many schools will trust the recommendation letter from a U.S. professor," said one student. It's time that we change this reality and build student trust and credibility of the letter of recommendation process from Chinese professors.

Dr. Nancy Snow is a visiting professor of Communications and Journalism at Tsinghua University