The frame serves as an aid in counting lost beans within an accurate area. It can be made from a light weight material such as wood, and should have inside dimensions of 1 foot by 8 feet. If a measurement wider than 8 feet is required, the frame can be repositioned as many times as necessary. There are several losses that can be measured. Preharvest loss is that which occurred before the actual harvest began and is not caused by any harvest operation.
Examples are hail damage or weather loss resulting from a delayed harvest.
Pre-harvest loss should be measured before any field operations begin. Total harvest loss is the sum of all losses from each operation plus any losses that may have occurred between operations. This is determined by measuring the loss after all field operations are completed and subtracting any pre-harvest loss. The most important measurement is that of an individual operation loss . This measurement assigns the loss to a particular operation and allows corrective action.