Rating is a term used in work measurement to assess the speed and effort put into a job of work by the worker. The British Standard Institute definition of the verb “to rate” is:
To assess the worker’s rate of working relative to the observer’s concept of the rate corresponding to standard rating. The observer may take into account, separately or in combination, one or more factors necessary to the carrying out of the task, e.g. speed of movement, effort, dexterity, consistency. (Term 22056).
In order to determine the time necessary to carry out a task or job it is not sufficient just to assess this by timing with a chronometer a worker carrying out the task or even estimating it. The worker might be working slowly or “extra quickly”. These are vague terms but neither would be satisfactory for the purposes of obtaining some sort of “standard time” for the job. What is needed is a time the “average”, trained, qualified worker would take to do the job.
This concept of the “average rate” at which the qualified worker would work is a very subjective one - it is a matter of opinion.
In essence, we do not want a time for doing a job quickly or slowly. We need a standard time for the job and not a time for any individual worker.
The solution is to assess the time actually taken by a qualified worker who knows the job and is properly trained to do it and then adjust this actual time to what it would have been had that worker been working at the standard rate. Thus, rating eliminates the need to search for that mythical standard worker and takes out of the equation the need for that worker to adjust his/her pace to the standard rate of working, something which is difficult to do.
So, to quote the BSI standard 3138 “Glossary of Terms used in Management Services” Term number 22074, standard rating is defined as
The average rate at which qualified workers will work, provided they adhere to the specified method, and are motivated, suited and accustomed to the task.
So, clearly, rating is highly subjective. To aid raters to conform with the universally accepted concept of rating there are sets of films/videos/CDs which demonstrate various jobs with their rates and have tests for training purposes.
Capable observers must be trained in the art of rating, first recognizing the standard rating and then, through practising, assessing against this standard other levels of rates of working. Rating scales have been developed. One of the original ones is Charles Bedaux’s, known as the “60/80 scale”. Bedaux considered that workers paid on a fixed daywork system without any financial incentive would normally do 60 minutes worth of work in an hour whereas one on a financial bonus scheme would get the work done on average one third faster, doing 80 minutes work in an hour (incentive rate). The rest of this “60/80 scale” was pro-rata. So, for example, a worker working twice as fast as this perceived “normal” 60 rating would be assessed as working at 120 rating.
This Bedaux scale was later converted to decimal form accepted by British Standard Institute which allocated a rating of 75 BS in place of Bedaux 60 and 100 BS rating replacing Bedaux’s 80 rating. The complete BS scale supercedes the corresponding Bedaux scale pro rata.
The mechanics of applying the system is explained in our Website Topics on (a) Time Study and (b) Rated Activity Sampling.