The seat-sharing deal struck by the NDA for the Bihar polls was guided by the BJP’s and JD(U)’s past poll performances in various regions. The BJP is contesting from at least 50% seats in Tirhut and Bhojpur, two regions where the JD(U) was relatively weak in 2015.
In Mithila, the JD(U) has an upper hand in seat allocation. In this region, the BJP is relatively weak and the JD(U) is strong. The seat allocations to parties in the ‘grand alliance’ do not have regional patterns as the vote shares of these parties were not high or low in specific regions.
Past performance
The JD(U) won over 47% of the votes it contested in the Mithila region in the 2015 Assembly election as part of the ‘grand alliance’, at least 6.6% points higher than its contested vote share in any other region.
The BJP is relatively weaker in Mithila; however, its vote share improved dramatically in the region after joining hands with the JD(U) in 2019. The RJD performed uniformly across all regions in 2015 while the Congress was relatively weaker in Tirhut and Bhojpur.
The table lists contested vote share (a party’s votes divided by total votes polled in seats contested by the party.)
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The regions were segregated based on data sourced from the Centre for the Study of Developing Societies (CSDS). The data for the 2019 election are calculated based on the leads secured in the Assembly segments.
Deal struck
The NDA’s seat-sharing deal is along the lines of the 2015 results, with the JD(U) contesting over 58% seats in Mithila. The BJP is fighting from over 56% seats in Tirhut, a relatively weaker area for the JD(U).
In the East, the Congress is contesting from 42% seats. This a region where it fared relatively better in 2019 but then lost.
The tables list the % of seats contested from each region in the 2020 polls.
Mapping the regions
The map depicts the constituencies in the five regions in Bihar: Tirhut (73 seats), Mithila (43), East (40), Magadh (65) and Bhojpur (22).
