# When to use a Scatter Chart?

A scatter chart works best when comparing large numbers of data points without regard to time. This is a very powerful type of chart and good when your are trying to show the relationship between two variables (x and y axis), for example a person's weight and height. A good example of this can be seen below.

The type of data used in this chart is generally statistical or scientific, and can suggest various kinds of correlation between the variables. In this type of chart the closer the plotted points are to making a straight line the stronger the relationship is between the two variables.

There are different types of correlation that a scatter chart will show. Correlations have two properties, direction and strength. The direction is determined by whether the correlation is positive or negative and the numeric value is determined by the strength of a correlation.

There are generally three types of correlation to look for:

Positive - This is when the variables move in the same direction. As one variable increases so does the other. Height and shoe size as an example are positively correlated.
Negative - This is when the variables move in opposite directions. As one variable increases, the other decreases. Time spent studying and time spent on playing games as an example are negatively correlated.
No correlation - There is when there is no apparent relationship between the variables. Video game scores and yearly salary as an example will appear to have no correlation; as one increases, the other has no effect.

If your chart does not show any relationship between the variables then this is not the best chart for your data.

If you want to learn how to easily make a scatter chart with ChartBlocks then we have an FAQ area with a step by step guide of how to make charts?