This paper first reviews available instruments that might be used by new technology-based small firms (NTSFs) as self-diagnostic tools to assess their positioning and plan their future development strategies. It makes a clear distinction between tools that are for self-diagnostic internal use by such ventures and the more established tools, such as Timmons 'fatal flaw analysis' and Bell-Mason, designed to assist venture capital investors in decisions whether to invest or not in a new company. The paper then analyses the application of the Klofsten Business Platform with its eight Cornerstones as a comparative diagnostic tool in over twenty case studies to the understanding of the early stages of development of new technology-based spin-off ventures from Australian and Scottish universities. The analysis is longitudinal over a period of up to six years for surviving companies. Survival rates for the sample have been compared with overall survival rates of spin-off and other new ventures in Australia.