1. Determining the Rating Factor
The most important and most difficult part of time study is to evaluate the speed or tempo at which the person is working while the study is being made.
The analyst most judge the operator’s speed while making the time study.
Definition of Rating
It is the process during which the time study analyst compares the performance (speed) of the operator observed with the observer’s (analyst) own concept of normal performance.
This rating factor is then applied to the observed time to obtain the normal time for the job.

2. Systems of Rating
Skill and effort rating
Westinghouse system of rating
Synthetic rating
Objective rating
Physiological evaluation of performance level
Performance rating
The most widely used is performance rating
Performance Rating
The speed of the operator is rated as a percentage with normal performance equal to 100 percent.
The range of human capabilities:
There are wide differences in capacities and abilities of individuals in every activity of life.
In general it is assumed that the best has roughly twice the capacity of the poorest.

3. Applying the previous assumption to the factory will mean that the fastest operator will produce approximately twice as much in a given time as the slowest operator.
Establishing a standard:
Each company should establish a standard for its own use.
Agreement should be reached as to what the normal standard level or performance should be in the plant.
Then the time for typical jobs in the factory with the operator working at a normal performance or speed should be established and filmed using motion pictures with 1000 frames per minute.
Motion pictures with 1000 frames per minute should be made for the operator performing a specific task and are then compared to the pictures of a normal worker to obtain the rating for the operator.

4. What affects the output of an operator?
Speed of muscular movements and method of doing the task.
Speed can be measured by the rating factor.
Method is defined as the specified motion pattern required to perform a given operation. The method should be standardized.