Quality Improvement Methods
51. Time Study & Work Measurement
a. Definition: In order to understand or improve a process it is often useful to know the time required to do the work involved. This can be done by direct observation of people doing the work (time study) or by developing the time necessary by combining known times for elements of the work (predetermined time standards) or by work sampling (random but statistically significant observations). Adjustments to the results of measurement may be necessary to reflect the physical demands and the pace at which work is executed. When properly done, these methods provide valid, accurate and useful measurements of the time and effort involved in work. Such information is useful when considering an intervention in current work practices that may change the amount of work time required. Prior training is usually necessary to properly gather data and assemble it into useful time information.
Time and motion study or time-study refers to the overall analysis of the time required to do work. It was initially developed in the early 20th century and is used to standardize work and evaluate workers' efficiency.
A researcher proposing a new procedure may wish to know how much time a particular new task will take. This can be developed through predetermined time standards or by observing similar work. Time requirements may be necessary for cost effectiveness analysis (see Section 10) that is needed for approving a new procedure.
- Barnes, Ralph Mosser, and Ralph Mosser Barnes. Motion and time study. Vol. 84. New York: Wiley, 1958.
- Pizziferri, Lisa, et al. "Primary care physician time utilization before and after implementation of an electronic health record: a time-motion study." Journal of biomedical informatics 38.3 (2005): 176-188.
- Burke, Thomas A., et al. "A comparison of time-and-motion and self-reporting methods of work measurement." Journal of Nursing Administration 30.3 (2000): 118-125.
- Predetermined time standards are available for healthcare. Time elements can be combined to determine the total time required for a particular situation. For example, MTM-HC is a standard database devoted specifically to healthcare activities available from The MTM Association for Standards and Research ( see http://www.mtm.org/systems.htm ).
c. Example: Research indicated the need to add an additional procedure to existing ones in the treatment of a particular diagnosis. The steps involved were well known but there was concern over the cost of the proposed change, particularly how much it would add to existing departmental staffing. In order to decide whether to proceed with the new procedure it was decided to determine the expected work time required. By observing work elements of similar procedures it was possible to calculate an accurate estimate of the time required for the new procedure. By work sampling the time currently spent by staff on existing work was determined as well as the availability of time for the new procedure. Once implemented additional time studies could be done to determine if the actual required time was the same as the expected time.
d. Steps: If the objective is to determine the time required for a particular item of work then the steps are:
1) Plan the study by considering the overall objectives and selecting the most appropriate time study method. Sometimes organizations have their staff themselves record the time taken for tasks that they themselves do, but this method often proves to be inaccurate.
2) Train observers regarding how to correctly gather data and so that all observers consistently follow the same procedure and that observations are made of work being done in a normal manner and not significantly affected by the observation process. It is particularly important that data be collected accurately. If sampled data then the sample must be sufficient to meet statistical standards. If data is to be collected on a random basis then the randomness must be truly random, perhaps generated by a computer program.
3) Conduct the observations and record times. In many healthcare situations this is challenging because staff may be doing multiple tasks simultaneously or the particular task being done is not obvious (such as work on a computer terminal or use of a telephone).
4) Review the data. Some observations may be biased or invalid and cannot be used. Individual time measurements will vary and sufficient observations will be necessary for a desired statistical level of confidence. Additional data gathering may be necessary.
5) Combine data as necessary and calculate desired metrics such as averages. Adjustments may have to be made concerning the pace of work - staff may be working faster or slower than normal, for example.
If the objective is to determine the percentage of time used for a particular item of work then work sampling methods may be used. This is a helpful technique that is less distracting for the staff than direct time study observations. steps for work sampling are:
1) Make preliminary observations to determine the variability of the data and the probability of observing items to be measured. This is necessary to determine necessary sample size.
2) Determine sample size for desired level of accuracy and confidence level.
3) Train observers as to how to make observations and what they are to record.
4) Select a method to initiate random observations in terms of their frequency and occurrence. The idea is to observe randomly so that all relevant times have an equally likely chance of being selected.
5) Make observations on random basis and record the data.
6) Using the results calculate the desired metrics and determine if the information meets the objectives of the study.
There are a number of ways to measure the time and effort involved in work. The particular approach will depend on what information is needed and the environment in which work is being done.