Who carried out the first opinion poll and why are they so popular?

This light-hearted and revealing clip examines the real purpose of polling voters and how you ensure the accuracy of a sample...

Transcript -- What's the point of Exit Polls?

Ever wondered how opinion polls work? As election fever grows - so does the importance of opinion polls which today are an essential part of modern political life. Political strategists, voters and the media all  lap up the data generated - but where does it come from? How many people do you need to interview to get trustworthy data? and just how easy is it to predict the future based on the opinions of the present?