Support for leftist National People’s Power (NPP) among voters has increased by 42 percent, putting them “well ahead” of the main opposition Samagi Jana Balawegaya (SJB), the president’s United National Party (UNP) and the ruling Sri Lanka Podujana Peramuna (SLPP), survey data showed.
“In Sri Lanka Opinion Tracker Survey (SLOTS) polling for September 2023, support amongst likely voters for the NPP/JVP increased to 42 percent (+9). This put them well ahead of the SJB on 22 percent, the UNP on 13 percent, and the SLPP on 8 percent,” the Institute for Health Policy (IHP) said in a statement Monday October 23 morning.
In the three months since June 2023, the most notable trends in the SLOTS MRP polling are a significant increase in support for the NPP/JVP, a fall in respondents saying they will vote for other minor or unnamed parties, and a modest upward trend in support for the UNP, the IHP said.
IHP and SLOTS director Ravi Rannan-Eliya was quoted as saying that this suggests that the current surge in support for the NPP/JVP is driven largely by undecided or floating voters opting for the NPP/JVP, instead of a swing away from the UNP which was the case earlier in the year.
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 September 2023 MRP estimates are based on 599 interviews conducted in September 2023, and 13,431 interviews conducted overall from 1 October 2021–11 October 2023, with a margin of error assessed as 1–3 percent for the SJB, NPP/JVP, UNP, SLPP, SLFP, ITAK, TMVP and the other parties. As the September update uses a more recent data set than the previous update, the IHP said, there are small changes in estimates of voting shares for previous months. A total of 62 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. The IHP said 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.