The ISI team basically treated it like a multiple sampling plan, which is often used by companies for product quality control. The statistical exercise of the ISI team was only about the efficacy of EVMs. The Election Commission of India (EC) maintains that EVMs are tamper-proof and the analysis of the ISI team is based on that assumption. One may argue that this is one way in which polls differ from constituency to constituency. If so, that might be contrary to the assumption of the ISI team that EVMs would behave similarly in all constituencies.

Source: Mint May 09, 2019 18:22 UTC