The total number of seats in the Parliament are allocated to parties proportionally to the number of votes received in the second vote of the ballot using the d'Hondt method. For example, to determine who is awarded the first list seat, the number of list votes cast for each party is divided by one plus the number of seats the party won in the region (at this point just constituency seats). The party with the highest quotient is awarded the seat, which is then added to its constituency seats in allocating the second seat. This is repeated iteratively until all available list seats are allocated.
How are the total numbers of seats allocated to parties?
proportionally to the number of votes received proportionally to the number of votes received proportionally to the number of votes received in the second vote of the ballot using the d'Hondt method