Robustness of the normal approximation of lead-time demand in a distribution setting

Previous studies criticize the general use of the normal approximation of lead-time demand on the grounds that it can lead to serious errors in safety stock. We reexamine this issue for the distribution of fast-moving finished goods. We first determine the optimal reorder points and quantities by using the classical normal-approximation method and a theoretically correct procedure. We then evaluate the misspecification error of the normal approximation solution with respect to safety stock, logistics-system costs, total costs (logistics costs, including acquisition costs), and fill rates. The results provide evidence that the normal approximation is robust with respect to both cost and service for seven major industry groups. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44: 165–186, 1997     

Iraq, 2003–2011: succeeding to fail

ABSTRACT

This study examines the US experience during the Iraq war, from the planning phase that began in 2001 to the withdrawal of US forces in 2011. It reveals a dearth of planning and intelligence leading up to the invasion; reluctance by conventional coalition military forces to conduct reconstruction, political and security capacity-building; and, later, full spectrum counterinsurgency operations. These forces took on some missions traditionally reserved for special operations forces, and they increasingly assumed diplomatic roles as they interfaced with the Iraqi leadership and local kingpins. Although these efforts yielded some impressive organizational learning and limited operational successes, they were hampered by lack of adequate preparation, a poor understanding of the human terrain, shortsighted strategies, and ultimately a dearth of political will to stay the course. The outcome was far from the model Middle East democracy envisioned by the invasion’s architects, and the American experience in Iraq instead became a cautionary tale for military intervention.