Colombo, Constitutional Reform, Politics and Governance

Suggestion to the Select Committee on Electoral Reform

by R.M.B. Senanayake

The Select Committee on Electoral Reform headed by Minister Dinesh Gunawardene has submitted a very good report making recommendations which will clean up our electoral politics by removing structures which encourage corruption.

It recommends a mix of the First Past the Post system and Proportional Representation. But unfortunately it has lost its way when determining the formula to allocate the extra seats to provide for Proportional Representation.

Mixed-member proportional representation is an attempt to combine a single-member electorate system under the First Past the Post system with a proportional voting system. In the German system half of the members of the legislature are elected in single-member district plurality contests like that recommended. The other half are elected by a party list vote and added on to the district members so that each party has its appropriate share of seats in the legislature.

The Select Committee has recommended a ratio of 140:70 on the first past the post system. The question is how to allocate the extra 70 seats on PR. The Select Committee recommended distributing them according to the votes polled only by the losers of each party. But this is unfair by the winning parties. It can be revised by distributing these seats according to the total votes polled by each party at the district level.

There are two methods- the remainder system and the proportional system. The largest remainder system is simple. In this approach, the first step is to calculate a quota, which is determined by taking the total number of valid votes in the district and dividing this by the number of seats. Suppose the district has 100,000 votes in the aggregate and there are 10 seats to be filled from PR in the district. Then the quota is 100,000/10=10,000. The quota is then divided into the vote that each party receives and the party wins one seat for each whole number produced. If a party receives say, 36,000 votes then it will get 3 seats and the remainder is 6000. Say 7 seats are allocated on this basis leaving a balance of 3 seats still to be allocated. After this first round allocation of seats is complete then the remainder numbers for all the parties are compared and the parties with the largest remainders are allocated the remaining 3 seats.

Another method is to allocate proportionately the PR seats according to the total votes by dividing them into the votes polled by each party as a proportion of the total votes polled in the district.


Consider the above example. Column 2 is the percentages of votes polled by 4 different parties and column 3 the seats won on the first past the post system. Column 4 is the seas allocated under PR on this method. Column 5 is the total seats won by each party and column 6 the percentages of seats won by each party under both first past the post and PR. Column 7 shows the difference between the seat entitlements on the percentage of votes polled. Column 8 is the squares of the numbers in column 7.

Party A is not fully compensated and suffers a shortfall of 3 seats. Party still has an excess of 9 seats above its percentage entitlement. Parties C & D also have a shortfall. In short there is no full proportionality. That won’t matter since the intention is partial proportionality and not full proportionality. But what is the extent of proportionality. This can be done by calculating a statistical index based on the sum of squared deviations. I found on the Internet an Index called the Gallagher Index which measures the degree of proportionality according to a scale from 0 to 100. The lower the index value the lower the disproportionality and vice versa. In this example the degree of disproportionality was 7.48 which is comparatively low on the scale of 100.
It would seem to me that the degree of disproportionality is comparatively low for this example which tries to simulate the percentages polled by the two main parties.

The Select Committee should apply this method or any other statistical measure to the results of the last general election and compute a similar index number to show the minor parties the extent of disproportionality.