The differences between a pass, merit or distinction grading in academic studies centred on effective interpretation of assessment questions and provision of “ideal” answers to the posted questions. 
Students of academic programmes should understand the expected learning outcomes from their levels of studies (typically stated in programme handbook) as they are expected to display the corresponding levels of cognitive development (order of thinking skills) in answering assessment questions.
Some background on levels of academic and vocational qualifications:
UNESCO’s International Standard Classification of Education (ISCED) plays a key role in the classification of vocational and general educational qualifications.
European Consortium for Accreditation in Higher Education (ECA)
Source: http://www.ecaconsortium.net/ecapedia/ISCED_levels_of_education
QAA (Quality Assurance Agency) UK Quality Code for Higher Education
SEEC Credit Level Descriptors for Higher Education (UK)
Higher learning assessment approaches seeks to validate the students “grasp” of taught topics, concepts ( objectives of the unit of study) i.e. the categories of learning domains:
Selecting methods of assessment
Source: http://www.swap.ac.uk/docs/Differentformsassessment.pdf
Different approaches must be adopted by students for aligning to the specific requirements of individual assessment methods i.e. reflective thinking, problem solving, analytical writing …………
Autodidaktikos 