SJB and NPP/JVP Lead in General Election Voting Intent

Photo courtesy of DW

The latest estimates of general election voting intent from Institute for Health Policy’s (IHP) SLOTS MRP model show the SJB and the NPP/JVP leading with 34% and 32% of voters’ support respectively, followed by the SLPP with 13%, the UNP with 7%, and ITAK with 5% in July 2024. Voting intentions in July have not changed substantially compared to the previous month. The July estimates are provisional and carry a margin of error of 2-3% for the two leading parties.

Compared to IHP’s July release, estimates of NPP/JVP and SJB support in June 2024 were revised +8 and -3 points, respectively. IHP polling director, Dr. Rannan-Eliya commented that there was unusual instability in the model estimates in recent months,which may reflect fluidity in voting intentions but that IHP is aiming to address this by increased numbers of interviews in coming months.

These estimates are for all adults, not just for likely voters. They are based on the January 2024 revision of the IHP SLOTS Multilevel Regression and Poststratification (MRP) model.

The July 2024 update is based on 19,015 interviews conducted with adults across Sri Lanka since October 2021, including 701 interviews during July and 497 interview in August 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 October 2021, according to what the multilevel model says about their probability of voting for various parties (‘post-stratification’) at each point in time.

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 and face-to-face interviews.

The July 2024 MRP estimates are based on 19,015 interviews conducted from October 1, 2021-August 19, 2024, including 701 interviews conducted in July 2024.

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.