176 Essentials of Inventory Management Metrics "You can't control what you don't measure." --Peter Drucker Before doing anything toward establishing methods to discover, an- alyze, and fix any discrepancies between actual on-hand stock lev- els and database record levels, you should take a snapshot of where you are now. There are two sets of numbers you should develop that relate to (a) inventory record accuracy (IRA) and (b) fill rate. IRA is a reflection of how well your shelf count and record count match. In other words, do your stock records accurately re- flect what is actually in the stockroom? Fill rate is a reflection of how effective your inventory is. Did you have what you needed when you needed it?