Read the following http://www.canadavisa.com/canada-immigration-substituted-evaluation.html
Canada's goal is to attract skilled workers who will become successfully established in Canada from an economic perspective. To this end, Canadian Immigration authorities have designed a selection system based on education, language skills, experience, age, arranged employment, and other adaptability factors that, in theory, demonstrates the applicant's likelihood of becoming economically established in Canada.
The Canadian government recognizes that the points awarded under the skilled worker selection system do not always accurately reflect an applicant's chances of successfully settling in Canada. As a result, Citizenship and Immigration Canada Officers are authorized to substitute for the criteria listed above their evaluation for the likelihood of the applicant becoming economically established in Canada, and to accept or refuse the applicant no matter what points are awarded.
Substituted evaluation is not the same as Humanitarian and Compassionate grounds. The Minister of Citizenship and Immigration, in compelling circumstances, may grant a Canada Immigration Visa to anyone who is otherwise inadmissible.