SUPPLEMENTARY COMPARISON: Measurements have been made at five national metrology institutes (NMIs) in the subject field of dimensional measurement using scanning probe microscopy. Four of the participating NMIs are in Europe, the fifth is in the Asia-Pacific region. Each NMI made measurements of four step height standards and two 1D grating standards. These are typical artefact standards used for dimensional nanometrology. Each participant used a different atomic force microscope to perform the measurements. The report lists the results obtained by the individual participants, as well as an analysis of the results and their uncertainties, based on calculation of the weighted means and En values. The results are in good agreement with one another.