One of the key academic issues that has arisen in this general election campaign has been the question of deciding which constituencies may be considered marginal and which ones are not. There are many ways in which a constituency may be deemed to be marginal that can range from emotion to scientific calculation.
I invented a formula for the calculation of the outer limit of marginality back in 2002. The inner limit of marginality will always be zero. The outer limit of marginality is a moving target from election to election. My marginality formula is designed to calculate an outer limit for marginality rather than guessing what might be marginal.
The symbols for this formula are M for marginality and D for the mid-point spread of the deposit level for the largest (L) and smallest (S) constituencies if everyone were to vote. This formula applies to electoral systems that use the first past-the-post method where the retention of the deposit of every candidate is calculated at one-eighth of the total votes cast in a constituency. The deposit is a fundamental statistical benchmark and can serve as a guide to determine where a survey should be conducted if marginality is the key element in the search for truly mixed political opinions. In marginal constituencies, the first and second candidates will always save their deposits owing to the fact that marginality always tends to move closer to zero as the difference between the first and second candidates.
In using electoral data from the general election that immediately precedes the one that is being measured, there can be challenges involving the emergence of strong third parties. Such was the case in the 2010 general election where 2007 data was used. In that situation, the votes for the second and third candidates from 2007 were added together and calculations made in relation to the first candidate to determine marginality.
The constituencies with the largest electorate (L) and the smallest electorate (S) must be divided by eight, and then their difference divided by two in order to calculate D which is the deposit mid-point. Therefore, the formula is: (L/8–S/8)/2=D
Once D is determined, then the statistical formula for calculating the outer limit of marginality (M) is: {(L/8)–D =(S/8)+D}=M.
Using my marginality formula with the 2015 revised list of electors, the following emerged:
L = Toco/Sangre Grande 30,148/8=3768.5
S = Port-of-Spain South 23,777/8=2972.125
3,768.5 – 2,972.125=796.375
765.375/2=398.1875
3,768.5 – 398.1875=3,370.3125
2,972.125 + 398.1875=3,370.3125
M=3,370.3125
Under the circumstances, M would be rounded down to the nearest whole number so that M = > 3,370.
When the value of M (> 3,370) was applied to the results of the 2010 general election on the basis of measuring the difference between the first and second candidates in all constituencies, the following marginal constituencies in Trinidad emerged with a difference between first and second that was less than the outer limit of marginality (> 3,370):
Arima (364)
Diego Martin North East (463)
Point Fortin (655)
Toco/Sangre Grande (700)
Diego Martin Central (993)
Lopinot/Bon Air West (1,003)
Diego Martin West (1,046)
La Horquetta/Talparo (1,079)
San Fernando West (1,251)
D’Abadie/O’Meara (1,343)
Tunapuna (2,297)
La Brea (2,564)
Port-of-Spain South (2,770)
St Ann’s East (2,776)
Moruga/Tableland (2,947)
Port-of-Spain North/St Ann’s West (2,968)
St Joseph (3,057)
When the boundary changes recommended by the Elections and Boundaries Commission in their report dated January 29, 2014, are factored in, the following constituencies emerged with adjusted first over second place figures:
Diego Martin North East (was 463 now 618)
Diego Martin Central (was 993 now 832)
Diego Martin West (was 1,046 now 1,269)
San Fernando West (was 1,251 now 1,084)
San Fernando East (was 3,627 now 2,610) (now in the marginal zone)
Port-of-Spain South (was 2,770 now 2,813)
Port-of-Spain North /St Ann’s West (was 2,968 now 2,751)
These marginal constituencies emerged on the basis of using the difference between the first and second candidates in the results of the 2010 general election and then re-calculating the differences between first and second candidates on the basis of boundary changes implemented by the EBC for the 2015 general election.
The results of the by-election in 2013 in St Joseph confirmed its continued status as a marginal constituency owing to the fact that its 2010 and 2013 electoral data fell inside of 3,370 (3,057 in 2010 down to 780 in 2013).
The application of a zoom lens to the data that captures the perennial marginal constituency of Tunapuna (2,297) by reducing the number of constituencies on a scientific basis using a value of M (>2,300) which falls inside the actual value of M (>3,370) would give scientific certainty (not emotional assertiveness) that those constituencies selected were marginal whichever way the result would go as long as they fell inside the zone of marginality. That would then constitute the data set for the next general election in respect of marginality.