The Printed Circuit Board (PCB) assembling production process is generally optimized to ensure very low levels of production errors (defects) so as to assure a higher quality product. In view of the number of components and solder joints in the products, and the very high demands placed on quality, the operation of this process is critical to the success of the products that are manufactured. A special class of the efficiency identification problem considered in this case relates to the occurrence of different kinds of production errors during the assembling process of the PCBs. However, the process of assembling often gets influenced by certain factors, which make some of the assembled PCBs to be defective. This chapter addresses the efficiency identification problem of a teleprinter-manufacturing company that assembles PCBs. The technique of Data Envelopment Analysis (DEA) is used to assess the efficiency of different types of PCBs.