Some of the points in your blog are really thought-provoking and introspective. One important point to further add is that a feedback loop in your process is very essential to understand if the process is chasing the right objective - which can be the wrong objective next moment. A process in forecasting to measure accuracy should not only just involve measuring absolute error or a relative error but also a bias error. Many a times bias error lets a planner know if the fundamentals or some basic assumptions have changed. In a retail context this becomes even more important since cost of conducting business not only involves the risk of holding stocks that are out of relevance but also risk of losing opportunity to hold stocks that are more relevant for today. Read blog http://infosysblogs.com/supply-chain/2008/09/the_right_level_for_measuring_1.html - this blog also talks about why forecasting at the right level of planning hierarchy is crucial to derive maximum milage out of your forecasting application. A forecasting process involving measuring Volume and mix accuracy are both crucial to help one decide the level in Forecasting.