A scatter chart (aka scatter gram and scatter plot) dapples a chart with points based on data for each item on the X and Y coordinates. For instance if you retained 100 law firms last year and you calculate for each firm its average billing rate that year, you can plot that figure on one axis and the firm’s size (in number of lawyers) on the other axis. A point for each firm marks the combination to the right and up from the intersection of the two axes.
Sort your data by size of firm and watch how the resulting scatter of points suggests a correlation: as firms grow in size, their blended rates rise. Or you might match size of firm and the number of the firm’s offices and see a gradual rise in both.
Whatever data you match, a scatter gram often shouts out a conclusion, since the eye readily spots clusters, open spaces, or patterns. Even further, with Excel if you click on the data points, you can create a trend line on sorted data that will confirm the pattern your eyes pick out or confirm the randomness of the data. For example, a scatter gram that shows the weight in pounds of your lawyers against their outside counsel fees approved year to date should show no pattern.