Subsection (1) provides for the establishment of a Scottish Parliament.
Subsection (2) provides for one member of the Parliament to be returned for each constituency by means of the simple majority system or “first past the post” system (73 members are currently returned on this basis - see Schedule 1).  These members are returned either at a general election (see sections 2, 3 and 5) or at a by-election to fill vacancies in constituency seats  (section 9).
Subsection (3) deals with the return of regional members from each of the eight regions by means of the additional member system of proportional representation, as provided for in sections 6, 7 and 8 (56 members are currently returned on this basis - see Schedule 1).  They are returned either at general elections (see sections 2, 3 and 5) or under section 10 in the case of a vacancy in regional seats.
Subsection (4) provides that the validity of any proceedings of the Parliament is unaffected by any vacancy in its membership.
Subsection (5) introduces Schedule 1, which provides for the constituencies and regions, the number of members to be returned per region and for alteration of the regions and of those numbers.
Commentary Details of Provisions