Regressions using individual port productivity indicators Table 11 presents the results using single productivity indicators which had previously been grouped together as Factor2. The results of individual variables that were of significance (Models Va and Vb) approximately match those obtained through the multivariate analysis with Factor2 in Model I. In several other cases, however, coefficients with low significance vary strongly in their values, indicating a high multicollinearity. For models Vd and Ve fewer observations were available, and the exclusion of a number of ports may at of Model I