[Note: page updates for new assessment requirements in progress May 2018]
Since National 5 courses changed in 2017–18 to move completely to external assessment and Higher courses are doing the same in 2018–19, only National 4 and Advanced Higher retain the old mandatory unit requirements beyond summer 2018.
Composing (the skill) and Composing Skills (the unit name) mean what they say… basically making up your own music. While the Course Assessment requirements tell you what’s required for an overall course award at all levels and are all you really need to know for Nat 5 and Higher, separate units at Nat 4 and Advanced Higher currently still require you to ‘Create original music by’:
(At National 4, from Music: Composing Skills (National 4) Unit Specification)
1.1 Identifying the compositional methods and music concepts used in given examples of music
1.2 Experimenting and using music concepts and compositional methods to develop and create original music
1.3 Developing musical ideas which convey their creative intention
1.4 Reflecting on their music and their creative choices
(At Advanced Higher, from Advanced Higher Music: Composing Skills Unit Specification)
1.1 Analysing how a range of advanced compositional methods and music concepts are used by composers for specific effect and the contexts which influenced their work
1.2 Experimenting and using complex music concepts and compositional methods in sophisticated and creative ways to develop, refine and create original music
1.3 Developing musical ideas which make musical sense and realise their creative intentions
1.4 Critically reflecting on their music and on the musical impact of their creative choices and decisions.
So the ‘composing’ part’s pretty obvious… you have to compose, and with greater musical accomplishment as well as more sophistication as you move up the levels. But both separate unit specifications and external assignments also require you to demonstrate that you can plan and evaluate your own work with similarly increasing awareness. While unit work is assessed as pass or fail by the teacher where the Nat 5 and Higher assignments are graded externally, you have some kind of log to complete for either.