scope:

The activity sampling frequency method is used to determine proportions of time in operating processes by means of random observations over a certain period of time. The results of activity sampling frequency methods and the results of other time recording methods both serve as foundations for operating planning and operating decisions [1].

The activity sampling frequency method is a statistical method to determine actual time data, which has been used and developed successfully for more than 40 years. For working studies and time studies, this is a comparably simple mathematical-statistical sampling technique. This is reflected for example by the advantage of the simple and economical operational benefit compared to many other analysis methods. Based on samples, "statements about the percentage frequency and/or the duration of mainly irregular processes and variables of any type for a freely selectable accuracy at a statistical certainty of 95 % can be derived" [2; 3].

The activity sampling frequency method is often used before REFA time recordings or as a followup check [1] and in most cases the codetermination committees are aware of it as well (the work council always has to be informed according to § 87 BetrVG - Works Constitution Act). The method is particularly suitable for the following purposes:

• tasks comprising a larger number of objects that need to be examined and/or observed

• processes and/or sub-processes where the time proportions which are of interest and which are to be determined are not too small (≥ 1 s)

• analysis, with results that do not need to meet the absolute claim with regard to their accuracy

The activity sampling frequency method is characterized by the fact that its application is not restricted to workers but can also refer to work objects and work and or operating equipment. The collected time data support the analysis and the evaluation of an initial situation, help to examine the efficiency of the measures implemented within the observed working system and are also used as a basis to determine the wages. [3]

Furthermore, the application of the activity sampling frequency method can help to analyse the exposure of individual employees or groups of employees by determining the time proportions and/or the times of critical situations (e.g. lifting and carrying of heavy containers, working under heat exposure). One application of this method, which is used frequently in operating practice, consists in the implementation of unproductive time studies in order to determine the delay allowance required for the target time [3].

Besides the activity sampling frequency method, also the observation ratio method was developed. However the observation ratio method is not the subject of this standard. Additional information on the observation ratio method can be found in [2; 3].