Starting with tools in the public domain and datasets that the Election Commission itself provides, data analysts can build huge datasets that a party can use for targeted advertising. With just the information on the electoral roll that is publicly available, analysts can get a person’s name, his or her father’s name, location (what booth they vote at), voter ID number and age.

In many large states of India such as Uttar Pradesh and Bihar, the caste of over 70% of the people can be determined simply by analysing their names. With a relatively simple code, a political party can identify the caste and religion of a large number of voters by analysing their last names (surnames), but there are some major complications in the process.

Different communities in different parts of a state sometimes use the same last name and some last names are not easy to classify. Certain . . .