In general, you should ideally ask for a letter that can
      substantially bring an added value to your application package,
      and communicate information that cannot be directly inferred from
      the rest of your application materials. For example, if I have no
      more to say than the fact that you have done a good job in a
      course and have obtained an A+, that wouldn't say much, since this
      information is already apparent from your academic transcript. If
      you're applying for a Ph.D. program, your letters should ideally
      come from those who can comment about your research track record
      and potentials, and this information can only be provided by
      someone who has supervised a research project done by you. For
      more information on the best practices regarding letters of
      recommendations, and graduate applications in general, read the amazing
        advice by Professor Mor Harchol-Balter at CMU. I myself
      benefited from this guide back when I was looking for Ph.D.
      programs. Best of luck for your search!
    
 
          
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            is my personal website, and any opinions expressed in this
            website are solely my own.)
          
Last Updated: September 2022