The Fit Details provides statistics that summarize how well the MDS proximities match the actual proximities as well as details about transformations when used.
Stress
The value of the stress function (Stress1) that was minimized in the fitting procedure. Stress can be between 0 and 1 with lower values indicating a better fit.
RSquare
The R2 value for linear fit of the actual or transformed proximities versus the predicted proximities.
Slope
If a ratio or interval transformation was used, the slope for the transformation is provided. It is the slope of the linear regression of the actual against transformed proximities.
Intercept
If an interval transformation was used, the intercept for the transformation is provided. It is the intercept of the linear regression of the actual against transformed proximities.