What makes for a successful startup? Or the converse–what are the Elements of Doom for all those Better Mousetraps? Since many of our Readers have Been There, Done That or Considering That, this blog posting by David Skok of VC Matrix Partners (with only minor holdings in healthcare) could be illuminating. Five factors are detailed succinctly and in plain English: market problems (timing, value proposition), business model failure, poor management, running out of cash and product problems. The calculation of CAC (Cost of Acquiring Customer)/ LTV (Lifetime Value of Customer) with a multiple of CAC:LTV at 1:3-5+ essential. To this Editor, these Elements also apply to later stages. For Entrepreneurs, “Why Startups Fail.” Hat tip to MedCityNews via Twitter.