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Kajang #GE13 Analysis

During the 13th General Election (GE13) we came up with a methodology for estimating individual voter support based on polling lane results from the 12th General Election (GE12). The results of these calculations were used to design a program to predict election results based on ‘swing’ parameters fed in e.g. ethnic support; age group; increasing partisanship etc. You can read a summary of this method at the end of this post.

Using the polling lane results of the 13th General Election we compared our previous calculations and come up with an estimated swing. This can help inform analysts and campaigners. For the upcoming by-election in Kajang we found that:

  1. Support for PR has increased by 5.08% since GE12, from 62.73% to 67.81%
  2. Support increased from Chinese voters of all ages
  3. Support decreased from Malay voters aged 43 and above
  4. PR is likely to retain the seat this by-election

1. Seat Statistics

Kajang is a DUN (State Assembly seat) located in a semi-urban parliamentary seat, P101.Hulu Langat, in Selangor.

Based on our GE13 data there were 38,965 voters of which 1,201 are early (postal) voters and the rest are regular voters. Due to complexities in our method 1,177 early voters were not analysed and are excluded from the rest of this report. For age ranges we are using the age of voters as of Dec 2013, not Dec 2012.

Out of the remaining 37,788 voters- 17,863 (47.27%) of the voters are ethnic Malays; 15,717 (41.59%) are ethnic Chinese; 3,900 (10.32%) are ethnic Indians and the remaining 308 (0.8%) are from other ethnic groups.

48.88% of the electorate are men, while 51.12% are women. The chart below illustrates the breakdown of voters by age group. Youth (ages 21-30) make-up 17.3% of the regular voters.

KajangVoters_ByAgeGroup

We do not have the electoral roll being used for this by-election, expect some differences in our statistics compared to the current roll.

As our previous calculations were based on Parliament seat results, we will use the same seat (P101.Hulu Langat) for this DUN. Voting results for DUN and Parliament were similar, with PR obtaining 56.82% of the popular vote (votes obtained / votes cast) in Hulu Langat and 56.84% of the popular vote in Kajang.

Due to the different voting patterns of Malay and Chinese voters, we will present separate analyses for these 2 groups in addition to the overall analysis. This will help provide a clearer picture for campaigners to use.

2. Analysis of Support (all ethnic groups)

Predicted GE13 Support (based on GE12 results)

Leaning BN: 4,767 (12.62%)

Fence-sitters: 9,316 (24.65%)

Leaning PR: 23,705 (62.73%)

Estimated GE13 Support (based on GE13 results)

Leaning BN: 3,597 (9.52%)

Fence-sitters: 8,567 (22.67%)

Leaning PR: 25,624 (67.81%)

‘Leaning BN’ means these voters have a >50% probability of voting for BN and ‘Leaning PR’ means these voters have a >50% probability of voting for PR. A >50% probability does not mean a guaranteed vote for either side. Fence-sitters are voters whose leaning could not be determined from the results.

By comparing the 2 datasets we can estimate the swing in support by the voters. For this analysis we will focus on the swing to and away from PR.

The following histograms illustrate the distribution of probabilities among voters. The blue bars represent ‘Leaning BN’ voters. The 50% bar represents the fence-sitters. The red bars represent fence-sitters and ‘Leaning PR’ voters – we combine both to show PR’s potential base.

KajangEst_Vs_Predicted

The majority of support for PR is still above 50%, the number of fence-sitters has had a slight decrease and the ‘Leaning BN’ voters have decreased as well. Support for PR has moved further to the right extending to the 90% level.

The average support for PR for each voter has increased by an average of 6.92%. For women the increase was 6.82%, while for men the increase was 7.03%.

When we group the voters by their est.swing, there is a clear pattern of movement towards PR. This histogram illustrates the number of voters by estimated swing to/from PR.

KajangVoterPop_By_EstSwing

8,983 voters (23.77%) experienced a drop in support. This decrease was too small to affect the outcome, as the average support from voters was 62.84%. The majority of the decrease was 5,886 voters reducing by 1% – 6%, meaning that BN-leaning voters swung further towards BN; PR supporters became fence-sitters; PR supporters remained supporters.

7,053 voters (18.67%) had little to no change. This covers fence-sitters and leaning PR/BN voters who did not move from their current level of support.

21,752 (57.56%) swung to PR. The majority of the swing was 10,064 voters increasing by 14% – 24%. Supporters became stronger, fence-sitters moved towards PR and BN-leaning voters moved towards fence-sitters/PR.

1,919 voters moved from fence-sitters and leaning BN towards leaning PR.

This chart shows the swing by age, calculated by averaging support values for voters by their age group. Average support for PR increased from voters of all ages, particularly ages 70 years and above.

KajangSwing_By_Age

When we combine this graph with the number of regular voters by age, we can see the impact of the swing.

KajangVoterPop_Swing_By_Age

The trend is voters aged 40 and below, and aged 70 years and above swung further to PR.

This chart illustrates the estimated level of support from voters. With PR getting support from 68% of the electorate, BN faces a difficult challenge to win the seat.

KajangEstSupport_Chart

Next we look at the support for Malay and Chinese voters, which will reveal patterns behind the average swing.

3. Analysis of Support (Malay voters)

Predicted GE13 Support (based on GE12 results)

Leaning BN: 4,515 (25.28%)

Fence-sitters: 2,131 (11.93%)

Leaning PR: 11,217 (62.79%)

Estimated GE13 Support (based on GE13 results)

Leaning BN: 3,597 (20.14%)

Fence-sitters: 2,215 (12.4%)

Leaning PR: 12,051 (67.46%)

The following histograms illustrate the distribution of probabilities among voters. The blue bars represent ‘Leaning BN’ voters. The 50% bar represents the fence-sitters. The red bars represent fence-sitters and ‘Leaning PR’ voters – we combine both to show PR’s potential base.

KajangEst_Vs_Predicted_Malay

The majority of support for PR is still above 50%, the number of fence-sitters has had a slight increase and the ‘Leaning BN’ voters have decreased as well. Support for PR has shifted to the right, however concentration remains high from 50% – 60%. This is significant because it means that PR support from Malay voters is not strong and there is potential for a swing.

The average support for PR for each voter has increased by an average of 0.22%. For women the increase was 0.1575%, while for men the increase was 0.2895%. Hardly any change, however the difference in swing between men and women is noticeable.

When we group the voters by their est.swing, there is a pattern of movement both away and towards PR. This histogram illustrates the number of voters by estimated swing to/from PR.

KajangVoterPop_By_EstSwingMalay

8,159 voters (45.68%) experienced a drop in support. The majority of the decrease was 5,354 voters reducing by 1% – 6%, meaning that BN-leaning voters swung further towards BN; PR supporters became fence-sitters; PR supporters remained supporters.

1,490 voters (8.34%) had little to no change. This covers fence-sitters and leaning PR/BN voters who did not move from their current level of support.

8,214 (45.98%) swung to PR. The majority of the swing was 4,896 voters increasing by 1% – 6%. Supporters became stronger, fence-sitters moved towards PR and BN-leaning voters moved towards fence-sitters/PR.

834 voters moved from fence-sitters and leaning BN towards leaning PR.

This chart shows the swing by age, calculated by averaging support values for voters by their age group. Average support for PR increased from voters aged 22 – 42 years, with some minor increases from voters aged 80 and 89.

KajangSwing_By_Age_Malay

When we combine this graph with the number of regular voters by age, we can see the impact of the swing.

KajangVoterPop_Swing_By_Age_Malay

The trend is voters aged 42 and below swung further to PR, with the swing increasing with each younger generation. The peak was at 5.73% from voters aged 22 years. Malay voters aged 43 and above however swung further away from PR by as much as 6.8%. It would appear that young Malays support PR while middle-aged and older Malays are on the fence or leaning towards BN.

After the swing, PR still has >50% support from Malay voters aged 22 – 56 years. 45% of Kajang’s Malay electorate are aged 21-40 years. If this youth voting pattern continues this by-election, PR can win support from the majority of Malays.

This chart illustrates the estimated level of support from voters. Despite the swing away from PR, PR still has support from 68% of the Malay electorate. However we have shown that this support is not strong and there is potential for BN to win votes from the middle-aged and older generation Malays.

KajangEstSupport_Chart_Malay

4. Analysis of Support (Chinese voters)

Predicted GE13 Support (based on GE12 results)

Leaning BN: 158 (1%)

Fence-sitters: 3,350 (21.31%)

Leaning PR: 12,209 (77.68%)

Estimated GE13 Support (based on GE13 results)

Leaning BN: 0 (0%)

Fence-sitters: 2,144 (13.64%)

Leaning PR: 13,573 (86.36%)

The following histograms illustrate the distribution of probabilities among voters. The blue bars represent ‘Leaning BN’ voters. The 50% bar represents the fence-sitters. The red bars represent fence-sitters and ‘Leaning PR’ voters – we combine both to show PR’s potential base.

KajangEst_Vs_Predicted_Cina

The majority of support for PR is still above 50%, the number of fence-sitters has had a large decrease and the ‘Leaning BN’ voters have decreased to zero. Support for PR has shifted far to the right, with a large concentration in the 79% – 91% range. This means support for PR from Chinese voters is very strong and BN’s main target should be the fence-sitters and voters with support from 50% – 60%, a total of 2,530 votes.

The average support for PR for each voter has increased by an average of 16.41%. For women the increase was 16.34%, while for men the increase was 16.48%.

When we group the voters by their est.swing, there is a pattern of movement both away and towards PR. This histogram illustrates the number of voters by estimated swing to/from PR.

KajangVoterPop_By_EstSwingCina

545 voters (3.47%) experienced a drop in support. The majority of the decrease was 322 voters reducing by 1% – 4%, meaning that PR supporters became fence-sitters or PR supporters remained supporters. We know that there are no more BN-leaning voters so this decrease was not caused by BN supporters moving further towards BN.

1,728 voters (10.99%) had little to no change. This covers fence-sitters and leaning PR/BN voters who did not move from their current level of support.

13,444 (85.54%) swung to PR. The majority of the swing was 8,428 voters increasing by 16% – 24%. Supporters became stronger, fence-sitters moved towards PR and BN-leaning voters moved towards fence-sitters/PR.

1,364 voters moved from fence-sitters and leaning BN towards leaning PR.

This chart shows the swing by age, calculated by averaging support values for voters by their age group. Average support for PR increased from voters of all ages.

KajangSwing_By_Age_Cina

When we combine this graph with the number of regular voters by age, we can see the impact of the swing.

KajangVoterPop_Swing_By_Age_Cina

The trend is voters aged 38 and below swung further to PR, with the peak at 21.64% for ages 37. Voters aged 70 years and above also swung to PR, with the peak at 24.78% for 89 year olds. There is a decline in the swing from ages 37 – 44 years, where the swing value decreases from 21.64% to 13.18%. Swing values stayed within a range of 13% – 14% for ages 44 – 60 years. Campaigners could look into why their support did not increase as much as the 22 – 38 year olds.

This chart illustrates the estimated level of support from voters. PR has support from 86% of the Chinese electorate, and this support is strong at 70% from 11,754 (74.8%) of the Chinese voters.

KajangEstSupport_Chart_Cina

5. Polling District Swing

The following is a list of polling districts (daerah mengundi) with their average estimated swing to PR and estimated support for PR based on GE13 results. The list is sorted alphabetically and only covers averages of regular voters.

  1. Bandar Kajang (59.37% support, +5.44% swing)
  2. Batu 10 Cheras (47.35% support, -9.02% swing)
  3. Kajang (72.28% support, +16.71% swing)
  4. Kantan Permai (53.98% support, +1.02% swing)
  5. Saujana Impian (56.89% support, +3.77% swing)
  6. Sungai Chua Dua Batu (81.88% support, +17.53% swing)
  7. Sungai Chua Empat (85.23% support, +18.96% swing)
  8. Sungai Chua Lima (83.38% support, +17.64% swing)
  9. Sungai Chua Satu (80.42% support, +19.43% swing)
  10. Sungai Chua Tiga (86.26% support, +18.06% swing)
  11. Sungai Kantan (44.49% support, -1.69% swing)
  12. Sungai Sekamat (49.74% support, -0.18% swing)
  13. Taman Delima (49.64% support, -4.05% swing)
  14. Taman Kajang Baharu (55.80% support, +10.96% swing)
  15. Taman Kota Cheras (64.10% support, +15.56% swing)
  16. Taman Mesra (56.59% support, -6.95% swing)

There is a pattern of strong areas (>50% support) becoming stronger and weak areas becoming weaker. One exception is Taman Mesra which went from 63.54% support to 56.59% support.

6. Summary

KajangEstSupport_Chart

In order to win, the candidate needs 19,483 votes (based on the previous constituency size of 38,965 voters). For BN, this means getting votes from early voters (1,177), BN-leaning voters (3,597), fence sitters (8,567) and 6,142 PR-leaning voters.

That would require a minimum of 24% of PR supporters (6142/25624) to swing to BN, assuming all the other groups support BN 100%. A better target would be 30% of PR supporters (7,688 voters).

It is unlikely for BN to achieve this due to the support PR received from all Chinese voters and Malay voters between 21 – 40 years old. While there is a possibility of a voter swing from older Malay voters, Malay votes alone cannot make up the difference and win the election for BN.

However BN can try to deny PR a strong majority thanks to Malay support for PR being concentrated at 50% – 60%. Additionally, the average support from Malay voters swung by less than 1%. This was an incumbent PR seat, so the low swing implies that Malay voters are not likely to swing much further towards PR apart from the young Malay voters.

Some strategies for BN campaigners to explore are:

  1. Focusing on campaign messages that appeal to middle-aged and older generation Malay voters.
  2. Women voters experienced a smaller swing to PR compared to men. This applies to all ethnicities. Issues that appeal more to women may help win back support.
  3. Increasing support in areas that swung away to PR. There might be something to be learned from the swing in Taman Mesra.

While Kajang looks like a sure victory, PR would gain political capital by increasing the winning majority.

Some strategies for PR campaigners to explore are:

  1. Increasing voter turnout, particularly among Malay youth and Chinese voters of all ages.
  2. Increasing support in areas that swung towards PR.
  3. Address the issues that reduced support from middle-aged and older generation Malay voters.
  4. Address local issues in areas that swung away from PR. Being in control of the state government gives PR an advantage in this.

7. Summary of Methodology

Voters are assigned to polling lanes based on their age and polling district (the area they reside in). A lane can hold 350-700+ voters, with a common size of 400-650 voters. From the results of the lane, we can assign a probability value to each voter in that lane.

For example if 400/600 votes went to BN, then the average probability of voters in that lane voting for BN is 66.67%. We can take the analysis a step further by adjusting for ethnicity, because each lane will have a fixed maximum number of ethnic voters. If there are 500 Malay voters in our example that means BN obtained at most 400 Malay votes and at least 300 Malay votes. This changes the probability of Malays voting for BN to a value between (300/500) to (400/500), or 60% – 80%. We take the average of this, giving a probability of 70%.

Note that this calculation does assume that turnout is evenly distributed by race. While that is not true, high voter turnout rates and ethnically dominant lanes reduce the impact of error. We tested both the average probability and the ethnicity-adjusted probabilities in our GE13 simulations and the ethnicity-adjusted probabilities yielded greater accuracy. We also had to take into account that voters migrate between constituencies. When that happens they bring their individual probabilities with them. This helps avoid inaccuracies that are introduced by focusing only on polling district results from previous elections.

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Written by politweet

March 7, 2014 at 3:26 pm

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