The number of measurements to be performed for time study analysis

The setting of time standards by work measurement is costly and consumes much time and effort. Therefore, the aims are to minimise time measurements while guaranteeing that the measurements are sufficient to provide a required statistical precision. This paper presents two methods for determining the required number of cycles to be investigated in order to set time standards. The first method utilises the Pareto principle to compute the required number of cycles, taking into account the cumulative weight of the elements. The second method computes the number of measurements needed to ensure the required inaccuracy of the standard time of the entire cycle. The proposed methods compute the optimal number of measurements to be performed by also taking into account economic considerations. This is done by balancing the cost of performing extra measurements with the benefits achieved by reducing the inaccuracies in the final time standards. [Received 4 November 2011; Revised 2 February 2012; Revised 5 July 2012; Revised 10 October 2012; Accepted 10 October 2012]