IHP’s Sri Lanka Opinion Tracker Survey (SLOTS) MRP provisional estimates of Presidential Election voting intent in Mar. 2024 show support for SJB leader Sajith Premadasa increasing to 41% (+2), reducing the gap with NPP/JVP leader AK Dissanayake who leads on 44% (-2). Support was little changed for Pres. Ranil Wickremesinghe at 8% (unchanged), and a generic SLPP candidate at 7% (-1).
Dr. Ravi Rannan-Eliya, director of the SLOTS poll, commented that a large uptick in support for Mr Premadasa in recent interviews is making the MRP model increasingly favour the possibility of a more general upward trend. But he cautioned that it would be best to wait one or two months to see if this was just noise in the polling or an actual trend.
These estimates use the IHP SLOTS Multilevel Regression and Poststratification (MRP) model (01/2024 revision). This update is for all adults and uses data from 16,671 interviews conducted from Oct. 2021 to 21 April 2024, including 527 interviews during Mar. 2024. 100 bootstraps were run to capture model uncertainty. Margins of error are assessed as 1–3% for March.
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 Presidential Election today, who would you vote for?’– in a multilevel statistical model that also smooths month to month changes. It then uses a large data file that is calibrated 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 to reflect underlying uncertainties in the model and to obtain margins of error.
About IHP
IHP is an independent, non-partisan research centre based in Colombo, Sri Lanka. The SLOTS 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
SLOTS combines interviews from a national sample of adults (ages 18 and over) reached by random digit dialling of mobile numbers, and others coming from a national panel of respondents who were previously recruited through random selection. IHP estimates voting intent using an adaptation of Multilevel Regression and Post-Stratification (MRP), with multiple imputation to account for uncertainties in its modelling, exploiting data from all SLOTS interviews to estimate voting in a particular month.
The March 2024 MRP estimates are based on 16,671 interviews conducted from 1 October 2021–21 April 2024, including 527 interviews conducted in March 2024. The margin of error is assessed as 2.7–2.9% for AK Dissanayake, Sajith Premadasa and 1.0–1.3% for Ranil Wickremesinghe and the other potential candidate. 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 General Elections.
The latest estimates from IHP’s SLOTS MRP model (revised 01/2024) confirm an increasing trend in support for SJB at the expense of the NPP/JVP. The SJB on 38% (+4) took the lead with all voters for the first time since 2022, ahead of the NPP/JVP on 35% (-2), the SLPP at 8% (unchanged) and the UNP at 5% (unchanged). The March estimates are provisional and are associated with a margin of error of 1–3% for the four leading parties.
Increasing support for SJB (38%) pushes it ahead of NPP/JVP (35%) in March 2024
Compared to IHP’s February release, IHP estimates of NPP and SJB support in Feb. 2024 were revised -7 and +5 points. Dr Ravi Rannan-Eliya, SLOTS polling director, commented that this was an unusually large revision, and was driven by a large uptick in SJB support in the early April interviews. But he cautioned that it would be best to wait a couple of months to see if this was just noise or a real trend.
These estimates are for all adults and not for likely voters. They are based on the 01/ 2024 revision of the IHP SLOTS Multilevel Regression and Poststratification (MRP) model. 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 have typically been 1–2% for most estimates in the past two years.
This March 2024 update is based on 16,671 interviews conducted with adults across Sri Lanka since Oct. 2021, including 527 interviews carried out in Mar. 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, which party would you vote for?’– in a multilevel statistical model. It then uses a large data file that is calibrated 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 to reflect underlying uncertainties in the model and to obtain margins of error.