In the Sri Lanka Opinion Tracker Survey (SLOTS) polling for August 2023, the NPP/JVP with 30% of likely voters remained modestly ahead of the SJB on 24%. Support for UNP remained at one in ten of likely voters (11%), with preliminary estimates indicating a drop in voters opting for unnamed parties.

The latest MRP estimates using the SLOTS polling data show little change overall in the position of major parties. 

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 August 2023 MRP estimates are based on 556 interviews conducted in August 2023, and 12,848 interviews conducted overall from 1 October 2021–13 September 2023, with a margin of error assessed as 1–3% for the SJB, UNP, SLPP, SLFP, ITAK and TMVP, and 5–6% for NPP/JVP the other parties. As the August 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.