Likert Scales:

Likert scales are categorical ordinal scale s used in social sciences to measure attitude.

Measurements at Likert scales usually take on an odd number of values with a middle point, e.g. "strongly agree", "agree", "undecided", "disagree", "strongly disagree". The middle value is usually labeled "neutral" or "undecided".

Forced-choice response scales are also used - that is, scales with an even number of responses and no middle choice. In this case, the respondent is forced to decide whether he/she leans more toward the agreement or disagreement.