By using software estimates, we can advance our best-case estimate at dinelent points within a project An important and difficult concept is narrowing the cone of ncertainty. Which is the best-case accuracy we can achieve in a project. Training estimators create cone-snaped projections which represent errors When the cone on uncertainty cannot be narrowed down to minimize errors. no proper estimate can be done or no control can be performed variables must be removed from the equation to narrow the cone. A poory eliminated variable will require more time and which wili result in a wider cone of influence