An opinion poll is a survey of public opinion from a sample of population about any issue. It is useful in many ways. In many cases, these are used to capture the public mood about an issue in discussion.
An Exit poll, which is the poll of voters, on whom they have voted for, right after exercising their suffrage, is better in the context of reliability. It has no bearing on the outcome of the election results, where as opinion pol does make a difference.
In general opinion polls are often used for capturing the mood of the people of the electorate before an election. Although the opinion polls give a theoretical estimate of the favorability of the people, it may not be reliable. Because of the fact that it is only a statistical estimate of favorability from a data sample collected from a proportionate amount of people.
An opinion poll helps a person to know the views of others which is very important while exercising his electoral rights. A person who is favoring a candidate does so because of his own reasons, but if an opinion poll comes out against the candidate he may reconsider his decision to support him/her.
This becomes very important factor in elections, as each person is living in a society and hence cannot make their decision in isolation without considering others opinions.
Also, an opinion poll helps the contestants to better their manifestos, introduce new ideas and project themselves better. An adulterated opinion poll poses a serious threat to this entire concept. Hence restrictions should be placed on who can conduct and publish opinion polls.
An opinion poll also becomes very important in this context as it may help a skeptical voter in deciding whom to vote for.
However, it has negative points as well. As the opinion polls may result in electors resigning from voting on the ground that their candidate may lose irrespective of their vote, it constitutes a bigger problem to our democracy.
In recent days, the UPA government is pushing Election Commission of India for a ban on opinion polls, whereas the opposition NDA is supporting them, contrary to their stance during last elections.
Such stand generally varies among parties on the basis of their favorability shown in opinion polls. But one must understand that a ban on opinion polls infringes the right to freedom of expression guaranteed by the Article 19(1) of the constitution and an opinion poll doesn't figure in the reasonable restrictions placed in the following sub clause of the same article.
The opinion polls also, as mentioned earlier, are not accurate in predicting the outcome of an election. As many polls during the 2004 general elections predicted the return NDA government but the UPA came to power. Also, many opinion polls predicted only a few seats for the AAP in Delhi elections -2013, but it made a fabulous debut. Hence, one should mind the fact that these cannot be the only factors to be considered before voting.
An opinion poll is an essential tool for the people of an electorate to decide on a candidate's suitability, they should not be banned but restricted to recognized pollsters only. On the other hand the exit polls which just show a real time update of an election can be kept with the existing restrictions.