Direct Stopwatch Time Study

Time study is a structured process of directly observing and measuring time required for completing a manual or machine work. Its done with the help of a timing device to establish the time required for completion of the work by a qualified worker, when working at a defined level of performance. The name ‘direct stopwatch time study’ got its name since we are directly watching the work and conducting time study using stopwatch.

Materials Required for conducting direct stopwatch time study are stopwatch, recording booklet/sheet and pen. We can also directly enter time in to spreadsheet using laptop.

We provide Time and Motion Study consulting service. Click the below button to know more.

Procedure

The first step to conduct a successful direct stopwatch time study is to select the operator to be studied. This step is applicable in the cases where more than one operator are performing the same task.

The operator should know all the knowledge related his work. Also, he should have developed skill in doing his job from his experience. We can consult with the supervisor of the section in selecting the operator with the above said criteria.

Record information about the standard operating practices, operations performed, equipment with which the operation is done, condition of the machine, quality required and the working conditions.

The second step involves breaking the entire operation into smaller elements or activities. This can be done by clearly defining the break point of each activity or element. Higher the number of activities split, higher is the accuracy of time study.

The activities are then timed using a stopwatch.

The recorded readings is called observed time.

We need to take some no of observations for considering the variation in the operation. From the observed times, remove outliers and take average of the observed times, so that we get the average of observed time for an activity or element.

In the next step we will convert observed time to Normal time.

Calculation of Normal time

Normal time = Observed time x Rating Factor.

We can use rating technique for calculating rating factor. Rating means gauging and comparing the performance or pace rate of a worker, against a standard performance level, set by the time study analyst.

The analyst observes the performance, compares it with the standard performance and arrive at a rating factor.

Rating Factor = Observed Rating / Standard Rating

Standard rating will be 100 always.

Observed rating will be above or below 100, according to the performance of the operator.

If the operator performs better than the standard performance the observed rating will be above 100, and it will be scaled according to the performance. If the operator perform below standard performance, rating factor will be below 100.

For knowing more about rating, please read a special article on ‘Rating in Time and Motion Study‘

Direct stopwatch time study example

A direct stopwatch time study needs to be conducted at a Workshop for machining of a particular job in a lathe. John is relatively inexperienced in this work and has only been at the organisation for 6 months, whereas Mark has been at this organisation for more than 20 years and is skilled at the particular said job.

The time study analyst first approaches John for taking time sample. Suppose John finishes machining of job in 12 minutes. The analyst gives a rating factor of 80. Then the normal time will be,

Normal Time = Observed Time x Rating Factor

The normal time of John will be 12 x (80/100) = 12 x 0.8 = 9.6 minutes.

Similarly, the Time study analyst approaches Mark for time study analysis. Mark being a skilled worker completes the job in 8 minutes. The analyst gives a rating factor of 120 to Mark.

The normal time of Mark will be 8 x (120/100) = 8 x 1.2 = 9.6 minutes.

Similarly each activity needs to be rated and normal time needs to be found out. The combined normal time of all the activities of an operation is known Total Normal time.

The next step is to find out the Standard Time. Unlike machines it is impossible to expect continuous work from operators because they need some relaxation. Adequate rest time for recouping energy needs to be given for operators. For this a Relaxation time is added to the normal time.

Calculation of relaxation time

Relaxation time = (Normal time x Relaxation allowance in percentage)

The relaxation time is added to the Normal time. Following is the answer to the question why we are adding relaxation time.

Its added because worker should get an opportunity to recover from the physiological and psychological effects of carrying out specified work under specified conditions. Its is also given for workers personal needs.

This relaxation allowances are calculated considering the factors such as average force exerted, posture, vibration, short cycle, restrictive clothing, monotony, eye strain, noise, temperature, dust and dirt etc.

Relaxation allowance will vary according to the work. Normally it will vary between 11% to 25%. I will explain the calculation of relaxation allowance later because its a lengthy subject.

Now we can calculate the standard time by the following formula, which is the output of time study.

Calculation of Standard time

Standard time = Normal time + (Normal time x Relaxation allowance in percentage)

It is only by finding out the Standard time shall we arrive at the Standard output per shift or day.

Example: Let’s continue with the earlier example involving the lathe. The Normal time was found out to be 9.6 minutes. The relaxation allowance was found to be 25%. Please note that this relaxation allowance is including tea break, but not the lunch break.

Therefore Standard Time = 9.6 + (0.25 x 9.6) = 9.6 + 2.4 = 12 minutes.

The available time per shift will be 450 minutes (Excluding lunch time)

The standard output per shift for the job will be (450/12 = 37.5) say 37.

Advantages of Time Study:

We can use standard time for the following;

(a) to plan future production and

(b) to evaluate performance of workers or of the production system as a whole.

(a) To plan future production:

(1) Estimation of equipment or machinery requirements.

(2) Estimation of production cost per unit in order to determine/fix selling price.

(3) Estimating manpower requirements.

(4) Taking makes or buys decisions.

(5) Balancing the work of operators constituting a group.

(6) Estimating delivery dates.

(7) Estimating times required for a specified inventory level generation.

(8) Estimation of labour costs.

(9) Making alternative investment decision in purchasing machines/equipment.

(10) Developing efficient plant layout and material handling arrangement.

(b) Time standards help in evaluation of performance as in following cases:

(1) The evaluation of productivity of various workstations.

(2) The development of individual or group incentive schemes for above average performance.

Disadvantages of Time Study:

The followings are the limitations of time study as a technique of setting production standards:

(1) We cannot establish time standards for jobs which do not have standard operating procedure. Because, it will be difficult to split the work element.

(2) In situations where it is difficult to define quality precisely standards and production incentives may cause deterioration in quality levels.

(3) It is not possible to maintain standard cycle time where piece rate system of wage payment exists, because each operators will try their level best for producing maximum no of products. Also there will be large variation in the cycle time of the activities.

(4) Labour unions may oppose the application of time study.

(5) Time study is applicable only where the work is visible. So it can only applied in manual job and not for thinking portions of the job.

(6) Only specific type of jobs which have identifiable starting and ending points can be timed accurately.

We can use work sampling where time study is not possible.

If you think this website is helpful to you and want to donate for supporting this website, please visit this donate page.

FREE ONLINE TIME STUDY SHEET

We have prepared an online time study sheet, for conducting time study easily, accurately, quickly and by anybody.

Please click here for Time Study Sheet

Thank You

Know more about our time study consulting service.

If you know any subject that can be related to manufacturing industry or industrial engineering, you can earn some income by becoming article contributor of this website. For knowing more about it, please visit Join us page.

You don’t need to have any experience in article writing, just knowledge on the subject is needed.

Also you can know more about our team of article contributors by visiting the about us page.