Sampling Methods for the Control of Physical Inventories.

Abstract : In business, industry, and various government installations the necessity of taking physical inventories of all goods on hand arises periodically. M. R. Bryson (1960) presented a method in which the stock is assessed by a combined use of stock taking count in conjunction with a continuous record of the number of units recorded for each stock item. All items in the establishment are classified to 'lots' and the inventory procedure proceeds separately for each lot. The procedure may be regarded as an estimation procedure of the inventory for each item in each lot in which a preliminary test of significance, the monitoring test, is used. The estimator used by Bryson is essentially the following. For all sampled items and for all items in all lots that failed the monitoring test, the complete count is used. For all nonsampled items in lots which passed the monitoring test, the record is used. This paper presents what may be an improvement of this estimation procedure with the help of a rotating sampling design and the use of a composite ratio (or regression) estimator for both the monitoring procedure as well as the computation of estimates of items inventoried. (Author)