Suan Dusit Poll says errors in its final poll in the lead-up to Sunday's governor election led the pollster to incorrectly predict that Pheu Thai candidate Pongsapat Pongcharoen would win.
In a letter signed by poll director Sukhum Chaloeysub, Suan Dusit Poll yesterday apologised to the public and to the media for the inaccurate results of its poll conducted on March 1-3.
"We accept the mistake and will look into the cause of the errors to improve the quality of our polls," Mr Sukhum said. "We will also ensure that every poll is well-planned and every piece of information will be double-checked."
The academic said the pollster would review the methods on how it solicits information from respondents.
Suan Dusit's poll asked voters about their intentions before they went to the polling stations on Sunday.
The polling results named Pol Gen Pongsapat as the clear favourite with 49%, followed by the eventual winner, MR Sukhumbhand Paribatra of the Democrat Party, with 39%.
MR Sukhumbhand received 1,256,349 votes in the election, while Pol Gen Pongsapat came in second with 1,077,899 votes.