There are three (or four) ways to proceed with
overhang seats:
 Take the number of overhang seats off from the other parties' seats (compensatory)
(e.g. National Council Elections in Austria, Scottish Parliament Election, planned system in Great Britain)
Characteristics: Reinforcement of unproportionality, unchanged total number of parliament seats.
 Allow the overhang
(e.g. Federal State Parliament (Landtag) of NorthRhine/Westphalia until 1965)
Increases total number of seats. Reduces Proportionality.
 Additional balance seats
(most election of the federal parliament systems, e.g. current NorthRhine/Westphalia)
Strengthened increase of the total mandate number. No (reduced) Disproportionality.
 Nonawarding of overhang seats
In this case, no overhang seat, develop by definition.
The nonawarding was applied occasionally in Bavaria.
These procedures are used all in different combinations.
Thus, there can be a distribution of additional balance seats
whose number is
limited, however (e.g. on the number of overhang seats).
The first method is most favorable for an overhanging party , the latter is the least favorable.
However, whether the electoral system remains meaningful
must be considered due to the various possible combinations of handling.
E.g. SaxoniaAnhalt, where additional balance mandates are distributed (method 3),
although the overhanging party receives less than 5 per cent of the party votes,
in this case seats are taken off the other parties (method 1).
This
leads to the effect that, in 1998, the SPD would have had
a substantially better result,
if the party had gotten less than 5% of the party votes.
Effects of different Dealings with Overhang Seats
Examples of these Effects
Parties 
Votes 
Seats
with PR 
Constituecies

Overhang
Seats 
  
Taken from
"Normal" 
Taken 
 
Remain

 
Compensation 
Compensator
seats 
Nationalists 
39.497 
4 
2 
 
 
4 

 
4 
 
6 
2 
Labour 
37.605 
4 
1 
 
 
3 
1 
 
4 
 
5 
1 
Liberal 
31.655 
3 
5 
2 
 
5 

 
5 
 
5 
 
Conservatives 
26.989 
2 

 
 
2 

 
2 
 
4 
2 
Green 
13.935 
1 

 
 
1 

 
1 
 
2 
1 
Socialists 
9.000 
1 

 
 
 
1 
 
1 
 
1 
 
SUM 
158.681 
15 
8 
2 
 
15 
2 
 
17 
 
23 
6 





 


 

 


Votes per Seat 

9000 


  
9402 

  
9000 
  
6330 

In this example the Liberal Party gains 5 constituencies and
consequently, 2 overhang seats. There are 15 seats to distribute in general (Normal Seats).
The Proportional Representation should be calculatetd by
the Divisor method with rounding down
(D'Hondt/Hamilton).
 Take the number of overhang seats off from the other parties' seats :
Taking the overhang seats from the other parties
will in this case reduce the number of seats of the
Socialists and Labour each by one. The total number of seats remains 15.
The Proportionality is reduced. Each Party needs 9402 votes per seat,
only for the liberals the ratio votes per seats is 6330.
 Leave the overhang without compensation:
The Liberals stay with their overhang seats,
the other Parties retain their seats by PR.
The PR is a little bit higher. The total number of seats is
increased by two overhang seats from 15 to 17.
There are 9000 votes for a seat, only the ratio for the liberals is 6330.
 Additional Balance seats:
To compensate the overhang Seats, additional balance seats are distributed,
thus one seat is rewarded
for 6330 votes.
The nationalists and the conservatives receive two seats, Labour and the Green Party
receive one balance seat. The total number of seats increases from 15 to 23.
 Not Awarding
Two of the five constituency seats are not awarded to the liberals.
The total number of seats remains at 15. For 9000 votes a party wins a seat.
Note: everything applies to
external overhang seats only.
Other possibilities apply to
internal overhang seats.
The introduction of additional balance seats for internal overhang seats leads to
additional problems
(Example BadenWuerttemberg)
© 2002 Martin Fehndrich