As the second phase of the Bihar Assembly elections concluded on Tuesday evening, attention turned to exit polls and their reliability. A review of past elections reveals mixed accuracy. In 2020, exit polls incorrectly predicted a narrow Mahagathbandhan victory, while the NDA actually secured a majority. An average of 11 exit polls underestimated the NDA by 17 seats and overestimated the Mahagathbandhan by 15 seats. The 2015 elections saw an even larger miscalculation, with pollsters vastly underestimating the RJD-JD(U)-Congress alliance's landslide win. Six exit polls on average underestimated the Mahagathbandhan by 55 seats and overestimated the NDA by 56 seats. These historical inaccuracies highlight the challenges pollsters face in predicting Bihar's complex electoral outcomes. Despite the Mahagathbandhan's overwhelming success in 2015, the alliance collapsed in 2017 when Nitish Kumar rejoined the NDA.
Exit Poll Accuracy in 2015 and 2020 Bihar Elections
In 2020, an average of 11 exit polls forecast a narrow Mahagathbandhan win at 125 seats against 108 for the NDA. However, the NDA narrowly won with 125 seats compared to the Mahagathbandhan's 110 seats. Exit polls underestimated the NDA by 17 seats. In 2015, six exit polls predicted a narrow Mahagathbandhan victory by just one seat over the majority mark of 122. Instead, the RJD-JD(U)-Congress alliance won decisively with 178 seats, while the NDA secured only 58 seats. The CNN IBN-Axis poll came closest with a prediction of 176 seats for the Mahagathbandhan. Despite this victory, the alliance dissolved in 2017 when Nitish Kumar returned to the NDA.
Source: Link