In Crystal Ball, you usually enter correlations one at a time using the Correlation dialog. Instead of manually entering the correlations this way, you can use the Correlation Matrix tool to define a matrix of correlations between assumptions in one simple step. This saves time and effort when building the spreadsheet model, especially for models with many correlated assumptions.
The correlation matrix is either an upper or lower triangular matrix with 1s along the diagonal. When entering coefficients, think of the matrix as a multiplication table. If you follow one assumption along its horizontal row and the second along its vertical column, the value in the cell where they meet is their correlation coefficient. The matrix contains only the correlation coefficients you enter.
If you enter inconsistent correlations, Crystal Ball tries to adjust the correlations so they don’t conflict. For more information on inconsistent correlations, see Specifying Correlations Between Assumptions.