5. Is there bias?

Bias means a tendency to favour some answers over others for some reason, usually to help sway the result in a way they want.

Example: Gathering unrepresentative data

A political party wants to find out if their ideas are going to be popular in the country as a whole. So they set up a survey asking only their party members.

This is clearly biased because they have excluded all non-party members from the survey. The data is unrepresentative of all people in the country.

Example: Asking leading questions

This is a question that encourages the person to answer in a certain way. The question might already contain the answer they want such as 'Curry is the nations' favourite food isn't it?'

Or it might have a built in assumption, such as 'How much will the price of football tickets go up next year?' It assumes that tickets will go up.

Conclusion:

Spotting a bias can be easy if it is very obvious, but it can be very difficult to spot if it is subtle. Survey questions should be carefully worded to avoid bias.