Inspecting and interpretation of a Scree plot involves two steps:
1. Draw a straight line through the smaller eigenvalues where a departure from this line occurs. This point highlights where the debris or break occurs. (If the Scree is messy, and difficult to interpret, additional manipulation of data and extraction should be undertaken).
2. The point above this debris or break (not including the break itself) indicates the number of factors to be retained.
In the example below (see Figure 2), the inspection of the Scree plot and eigenvalues produced a departure from linearity coinciding with a 6-factor result. Therefore this Scree Test indicates that the data should be analysed for 6 factors.