A scattergram or scatter plot defines a relationship between two variables related to cause and effect. According to the American Society of Quality, a scattergram illustrates pairs of numerical data on graphs with one variable on each axis to explore the relationship between them.
On a scattergram, points fall along a line or curve where variables are correlated. Scattergrams also identify root causes of problems, determine objectively if a cause and effect are related, and figure out if two effects that appear to be related are caused by a similar course. Scattergrams can be constructed in MS Excel or statistical software such as XLSTAT.