The Psychology of Management by Lillian Moller Gilbreth

overcome fatigue. Dr. Taylor spent years in determining the percentage of rest that should be allowed in several of the trades, beginning with those where the making of output demands weight hanging on the arms; but there is still a great amount of investigation that could be done to advantage to determine the most advisable percentage of rest in the working day of different lengths of hours. Such investigation would probably show that many of our trades could do the same amount of work in fewer hours, if the quantity and time of rest periods were scientifically determined. Again, there is a question of the length of each rest period. It has been proven that in many classes of work, and especially in those where the work is interrupted periodically by reason of its peculiar nature, or by reason of inefficient performance in one of the same sequence of dependent operations, alternate working and resting periods are best. There is to be considered in this connection, however, the recognized disadvantage of reconcentrating the attention after these rest periods. Another thing to be considered is that the rate of output does not decline from the beginning of the day, but rather the high point of the curve representing rate of production is at a time somewhat later than at the starting point. The period before the point of maximum efficiency is known as "warming up" among ball players, and is well recognized in all athletic sports. As for the point of minimum efficiency, or of greatest fatigue, this varies for "morning workers," and "night workers." This exemplifies yet another variable. The minuteness of the sub-fields that demand observation, is shown by an entry in the Psychological Index: "1202. Benedict, F.G. "Studies in Body--Temperature." 1. Influence of the Inversion of the Daily Routine; the Temperature of Night Workers."[14] SELECTION OF BEST UNIT OF MEASUREMENT NECESSARY AND IMPORTANT.-- Selecting the unit of measurement that will of itself reduce costs is a most important element in obtaining maximum efficiency.[15] This is seldom realized.[16] Where possible, several units of measurements should be used to check each other.[17] One alone may be misleading, or put an incentive on the workers to give an undesirable result. The rule is,--always select that unit of output that will, of itself, cause a reduction in costs. For example:--In measuring the output of a concrete gang, counting cement bags provides an incentive to use more cement than the instruction card calls for. Counting the batches of concrete dumped out of the mixer, provides an incentive to use rather smaller quantities of broken stone and sand than the proportions call for,--and, furthermore, does not put the incentive on the men to spill no concrete in transportation, neither does it put an incentive to use more lumps for Cyclopean concrete. Measuring the quantity actually placed in the forms puts no incentive to watch bulging forms closely. While measuring outputs by all these different units of measurements would be valuable to check up accuracy of proportions, accuracy of stores account, and output records, the most important unit of measurement for selection would be, "cubic feet of forms filled," the general dimensions to be taken from the latest revised engineer's drawings. NECESSITY FOR CHECKING ERRORS.--Dr. Stratton says,--"No measurements, whether they be psychic or physical, are exact beyond a certain point, and the art of using them consists largely in checks and counter checks, and in knowing how far the measurement is reliable and where the doubtful zone begins."[18] Capt. Metcalfe says,--"Errors of observation may be divided into two general classes; the instrumental and those due to the personal bias of the observer; the former referring to the standard itself, and the latter to the application of the standard and the record of the measurement."[19] The concrete illustration given above is an example of careful checking up. Under Scientific Management so many, and such careful records are kept that detecting errors becomes part of the daily routine. SUMMARY RESULTS OF MEASUREMENT TO THE WORK.--Under Traditional Management, even the crudest measurement of output and cost usually resulted in an increase in output. But there was no accuracy of measurement of individual efficiency, nor was there provision made to conserve results and make them permanently useful. Under Transitory Management and measurement of individual output, output increased and rewards for the higher output kept up the standard. UNDER SCIENTIFIC MANAGEMENT BETTER METHODS AND BETTER WORK RESULTS.--Under Scientific Measurement, measurement of the work itself determines