Sajith Premadasa Reduces Gap with A.K. Dissanayake in Presidential Election

Photo courtesy of Al Jazeera

The Institute for Health Policy’s (IHP) Sri Lanka Opinion Tracker Survey (SLOTS) MRP provisional estimates of presidential election voting intent in March 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 President 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 (January 2024 revision). This update is for all adults and uses data from 16,671 interviews conducted from October 2021 to 21 April 2024, including 527 interviews during March 2024. 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 October 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.

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 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 A.K. 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.