From the SSHRC website (though perhaps this only applies to MA students?):
Multidisciplinary committees evaluate applicants based on:
Academic Excellence
Weighting: 60%
Academic excellence—as demonstrated by academic transcripts, awards and distinctions.Research Potential
Weighting: 30%
Quality of analytical skills, ability to think critically, ability to apply skills and knowledge, judgement, originality, initiative and autonomy, determination, and ability to complete projects within an appropriate period of time—as demonstrated in the description of the degree program and by work experience, research contributions, letters of appraisal and, if applicable, the departmental appraisal. Communication Skills
Weighting: 10%
As demonstrated in the description of the degree program and, if relevant, by work experience, community involvement and other extracurricular activities, as well as by letters of appraisal, the quality of presentation of the application and, if applicable, the departmental appraisal.