# What is correlation?

The Starred dashboard calculates the impact of a particular (service) aspect on the Net Promoter Score. This impact is stated as a correlation coefficient.

With this correlation, you analyse to what extent this aspect and the Net Promoter Score fluctuate together, that is correlated.

A correlation coefficient can be both negative and positive and is displayed in a figure between -1 (perfect negative correlation) and +1 (perfect positive correlation). A correlation coefficient of 0 means that there is no correlation.

A positive correlation means that two variables move in the same direction: if one score increases, the other score increases. Or if one score lowers, the other score lowers.

A negative correlation means that both variables move in opposite directions: if one score increases, the other score lower. Or if one score lowers, the other score increases.

A score of 0 indicates that there is no correlation, the movement of one score does not relate to the fluctuation of the other score. For example, if one score increases, the other score remains the same. If one score lowers, the other score remains the same.

Please note. Correlation indicates a certain relation between the aspect and NPS, without implying causation.