4.4.4. Performance factor. The performance factor is considered to take into account the ‘downtime’. The downtime factors are based on many series of case histories studied over a long period of time. These factors relate the actual time needed to do a job to the estimated time to do the same job. Since, downtime relates to the non-production time, these factors will always be more than 1 (between 1 to 2). This ratio of actual time to estimated time to do a job is known as “Performance factor”, R, which may be written as.
R = T_a/T_c
Where T_a = actual time needed to do a job
T_c = estimated “ to do a job.