Provides a graphical means for assessing and communicating the relationship between two variables.
|When to Use||Purpose|
|Start of project||Assists in developing alternatives measurement systems when a variable is difficult or expensive to measure. Highly correlated and logically linked alternative variables can be used as substitute variables.|
|Mid-project||The first rule of data analysis is to graph the data before running any statistical tests. You can use scatterplots along with any statistical tool that tests for relationships between variables (for example, regression).|
|Mid-project||Assess whether an input (X) has a strong relationship with an output (Y) to help eliminate noncritical X's from consideration.|
|Mid-project||Evaluate two inputs to eliminate inputs that duplicate the same information (for example, inputs of Degree Obtained and Years of School are likely to explain the same variation of the output). This case is used primarily in multiple regression with many variables.|
|End of project||If you used this tool earlier as part of the validation of the measurement system, you should reapply it to the improved process to again validate the measurement system.|
One or two pairs of numeric variables (can be continuous or discrete).