It is a proportional electoral system, percentage of seats should be similar to the percentage of votes won
No wasted votes, all votes are used and the voter feels more valued
Coalition governments are normal
Roughly how it works:
It is a hybrid system uses both FPTP + a closed list system
First vote chooses a member for their local constituency
The second vote (closed list) is used to select a political party - it acts as a 'top up' to the constituency vote - makes the overall vote more proportional
2016 Scottish Parliament election result: SNP 45% of the vote = 63% of seats. (Turnout 56%)
Advantages:
Proportional
Each voter has a single constituency representative
Gives voters a wider choice (First + second choices means that they can choose a candidate from a certain candidate for their first choice and a different party for their second choice)
A coalition gov is more likely (possibly a disadvantage too?)
Disadvantages:
Closed list - chosen by party.
Having two types of representative may create animosity between them, those elected via party lists may have been seen as having 'got in via the backdoor'
Smaller parties are less well represented then under a fully proportional system.