The conductance of transparent conducting oxide films as a function of their coverage has been investigated in situ. The films have been prepared by means of reactive evaporation of In in the presence of oxygen on the glass substrate at different substrate temperatures. The analysis shows that island growth, percolation, coalescence, and ohmic stages can be identified. Critical parameters of the films can be determined during the growth, such as anisotropic and percolative growth modes, resistivity, a lower limit of the effective dopant concentration. The technique shows a potential for in-depth characterization of very thin film growth.