In Sri Lanka Opinion Tracker Survey (SLOTS) polling for September 2023, support amongst likely voters for the NPP/JVP increased to 42% (+9). This put them well ahead of the SJB on 22%, the UNP on 13%, and the SLPP on 8%.

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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. Dr Rannan-Eliya, the SLOTS director, commented 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.

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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 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% 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, 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. 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.

Funding

The SLOTS has 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, but the sponsors play no role in the study design, analysis, or interpretation of findings. Interested parties can contact IHP for more detailed data and results.