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e-mail: info@ihp.lk web: www.ihp.lk twitter: @ihplk

PRESS RELEASEEMBARGOED UNTILFOR FURTHER INFORMATION CONTACT

Date: 28 February 2024
Time: 11:59 PM Sri Lanka Time

Secretary/Administrator
Email: info ‘at’ ihp.lk

TO CONTACT LEAD INVESTIGATOR
Dr. Ravi Rannan-Eliya
Email: ravi ‘at’ ihp.lk Twitter: @ravirannaneliya

NPP/JVP maintains lead in voting intentions,with continuing increase in SJB support
IHP MRP General Election Voting Intentions Update January
2024
The latest estimates from IHP’s revised SLOTS MRP model (revised 01/2024) show nosubstantial change in General Election voting intentions in January 2024 compared to theprevious month. NPP/JVP continues to maintain a lead with 40% of Sri Lankan adult voters(-1 since previous month). The SJB leads the rest at 30% (+2), the SLPP at 8% (NC), the UNP
at 6% (-1), and ITAK at 4% (NC). The January estimates are provisional and are associatedwith a margin of error of 1.0–3.6% for the four leading parties.

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These estimates are based on the Jan. 2024 revision of the IHP SLOTS Multilevel Regression
and Poststratification (MRP) model, which smoothed monthly changes and reduced monthly
fluctuations due to sampling noise. Unlike previous months which highlighted voting intent inlikely voters, these estimates are for all adults. IHP is working on improving its likely voter
model and will resume release of voting intent in likely voters in a future update. But it should
be noted that differences in voting intent shares between all adults and likely voters havetypically been 1–2% for most estimates in the past two years.
This January 2024 update is based on 15,590 interviews conducted with adults across SriLanka since Oct. 2021, with 506 interviews carried out in Jan. 2024. IHP’s SLOTS MRP
methodology first estimates the relationship between a wide variety of characteristics about
respondents and their opinions – in this case, ‘If there was a General Election today, whichparty would you vote for– in a multilevel statistical model”. It then uses a large data file that iscalibrated to the national population to predict voting intent in each month since Oct. 2021,
according to what the multilevel model says about their probability of voting for various parties(‘post-stratification’) at each point in time. The multilevel model was estimated 100 times toreflect underlying uncertainties in the model and to obtain margins of error.
Previous reports available from ihp.lk
Institute for Health Policy, March 2023, “IHP MRP Voting Intentions Estimates February
2023. Voters consolidate around the NPP/JVP, SJB and ITAK, with NPP/JVP taking a clear
lead”, SLOTS Report #2023-06.
Available at: https://ihp.lk/publications/docs/SLOTSReport202306.pdf
Institute for Health Policy, April 2023, “Little change in voting preferences in March, withNPP/JVP maintaining a clear lead over SJB, amidst possible signs of a UNP rise. IHP MRPGeneral Election voting intentions update March 2023”.
Available at: https://ihp.lk/news/pres_doc/IHPPressRelease20230419.pdf
Institute for Health Policy, May 2023, “NPP/JVP maintains a lead, but loses support to UNP
and other parties, whilst SJB flatlines. IHP MRP General Election voting intentions update
April 2023”.
Available at: https://ihp.lk/news/pres_doc/IHPPressRelease20230525.pdf

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Institute for Health Policy, June 2023, “NPP/JVP support fell to 23% behind SJB on 26%,
whilst support for UNP and SLPP rises amongst likely voters during May 2023. IHP MRPGeneral Election voting intentions update May 2023”.
Available at: https://ihp.lk/news/pres_doc/IHPPressRelease202306301.pdf
Institute for Health Policy, July 2023, “Support for NPP/JVP and SJB fell, with evidence ofgrowing vote disillusionment with all established parties in June 2023. IHP MRP General
Election voting intentions update June 2023”.
Available at: https://ihp.lk/news/pres_doc/IHPPressRelease20230727.pdf
Institute for Health Policy, August 2023, “Support for major parties changes little in July, withNPP/JVP and SJB ahead, but large numbers of voters uncommitted. IHP MRP General
Election voting intentions update July 2023”.
Available at: https://ihp.lk/news/pres_doc/IHPPressRelease20230821.pdf
Institute for Health Policy, September 2023, “NPP/JVP retain an edge over the SJB amongstvoters in August. IHP MRP General Election voting intentions update August 2023”.
Available at: https://ihp.lk/news/pres_doc/IHPPressRelease20230925.pdf
Institute for Health Policy, October 2023, “NPP/JVP leads with 42% of likely voters, ahead of
the SJB (22%) and UNP (13%) in September. IHP MRP General Election voting intentions
update September 2023”.
Available at: https://ihp.lk/news/pres_doc/IHPPressRelease20231023.pdf
Institute for Health Policy, November 2023, “Little change in voter intentions in October, withNPP/JVP consolidating its lead at 40%. IHP MRP General Election voting intentions update
October 2023”.
Available at: https://ihp.lk/news/pres_doc/IHPPressRelease20231123.pdf
Institute for Health Policy, January 2024, “NPP/JVP on 39% of all adults, ahead of SJB(27%) and SLPP (10%) in December ’23. IHP MRP General Election voting intentions
update December 2023”. Available at:https://www.ihp.lk/sites/default/files/press-release/IHPPressRelease20240126.pdf

About IHP
IHP is an independent, non-partisan research centre based in Colombo, Sri Lanka. TheSLOTS lead investigator is Dr Ravi Rannan-Eliya of IHP, who has trained in public opinion
polling at Harvard University and has conducted numerous surveys over three decades.

Methodology details
SLOTS combines interviews from a national sample of adults (ages 18 and over) reached byrandom digit dialling of mobile numbers, and others coming from a national panel ofrespondents who were previously recruited through random selection and face-to-faceinterviews. IHP estimates voting intent using an adaptation of Multilevel Regression and PostStratification (MRP), with multiple imputations to account for uncertainties in its modelling,exploiting data from all SLOTS interviews to estimate voting in a particular month.
The January 2024 MRP estimates are based on 506 interviews conducted in January 2024,
and 15,590 interviews conducted overall from 1 October 2021–26 February 2024, with aPage 3 of 4

margin of error assessed as 0.4–1.4% for the UNP, SLPP, SLFP, ITAK, SLMC, CWC, and2.6–3.6% for NPP/JVP, SJB and the “other” parties. The January update uses a revised
model, so estimates will be smoother and will differ a little from previous estimates. A total of
100 stochastic simulations were used in the modelling to estimate margins of error.
MRP is a method that is increasingly used by polling firms in other countries to leverage small
samples, most notably by YouGov which used it to forecast results of the UK Brexit
Referendum and recent UK general elections. All estimates are adjusted to ensure the sample
matches the national population with respect to age, sex, ethnicity, socioeconomic status,education, geographical location, and voting in the 2019 Presidential and 2020 GeneralElections.

Funding
The SLOTS survey has previously been funded by the Neelan Tiruchelvam Trust, the UK
National Institute for Health and Care Research (NIHR), The Asia Foundation in Sri Lanka,and others. Current fieldwork is financed by the IHP Public Interest Research Fund and others.
The sponsors play no role in the study design, analysis, or interpretation of findings.
Furthermore, the survey findings do not necessarily reflect the views or positions of past andpresent funders. Interested parties can contact IHP for more detailed data and results.

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