This is a question I hear often from young undergraduates preparing to study abroad. I do not claim to be the expert but here is my take on the topic.
In the absence of any outstanding factor tilting the selection process, here is my list:
First level of screening:
- Bare minimum (note: not cutoff) scores in TOEFL and GRE
Second level of shortlisting (in that rough order)
- Reputation of undergraduate school/college/ university at the university (often based on good or bad experience with previous students they have taken or reputation or renown etc; can also depend on personal experiences of members of the admissions committee may think; note: admissions committee can include Indians) — this is the reason IITians may do better than others.
- Class rank and performance (and so toppers may get preference here)
- Reference letters and SOPs (SOPs with clarity of purpose, and alignment of goals and program chosen may score high; references that are aligned to SOP may work better)
- If everything else is similar, then they are likely to use test scores. (Note: The test scores universities quote may be what people who got in scored but it may not be that they used a cut-off to screen candidates.)
But there can be outstanding aspects that may give somebody an edge. These outstanding aspects keep changing with the times and are often specific to universities. Some examples:
- A reference letter from somebody who is known to and respected by the admissions committee.
- Outstanding initiatives, experiences and achievements aligned to the SOP. (Ex: International awards, outstanding research work and indication of leadership potential)
- A very strong reason to be at that university and strong reason for the university to bring you in to strengthen their important program.
- A reference by somebody respectable from the department itself.
Needless to say, something done extremely poorly can also change the process and tilt it to the wrong side — for example, extremely poor test scores, poor english skills etc.