Two major aspects of this relationship are the strength and the slope of the socio-economic gradient. When a student's actual performance is not the same as would be expected given his or her socio-economic status (as when the dots in Figure 1.6.5 are far from the dark line), the socio-economic gradient is considered to be weak. When socio-economic status becomes a good predictor of performance (and the dots in the figure are close to the dark line), then the gradient is considered strong.