Job/task Completion Standards (Job Goals)

   

Materials (physical and electronic)

   

Equipment/tools Hardware and Software

Workspace Layout

Environment (Physical & Social)

Work Methods

Example Jobs

• Workers/consumers
• Values/training
• General education
• Specific training
• Recent training
• Size/strength
• Physical and mental impairments
• Cultural factors
• How one feels on any given day
• Fatigue
• Injuries & illnesses

Observed time

• Observe and use a stopwatch to record start/stop times for desired time study elements --
• Stop watch
• Use video recordings to detemine start and stop times for desired time study elements.
• Use instrumentation/software

Statistics

• expect time variations from one element to te next.
• Descriptive statistics: Mean, median, standard deviation, minimum, maximum, skewness
• Upper and lower percentiles
• Frequency Distribution:

Example 1:How is determining the time required to complete a task analogous to determining the height of a door opening?

Example 2: Text entry: How much time is required to send a 50 character text message using the touch screen and using voice inputs

• Measure the number of characters per second for each method
• Web app for determining text entry time
• Practice both methods until comfortable with each
• Sample data:

• Speed differences among touch screen and speech are obvious -- what about accuracy?
• How much time should be allocated to send a 50 character text message?
• Discuss task and individual factors that may affect performance.
• References:
  • Some texting statistics

Example 3: Use of an AED

• How much time should be allocated for the use of an AED? (How much time do you need to find one?)
• How much time do you have?
• AED"

Learning curves

• see:
  • Learning curve references
  • Karger DW, Hancock WM. Advanced work measurement. Industrial Press; 1982.
• Make a list of factors that affect
  • the intercept of the curve on the vertical axis.
  • where the curve plateaus.
  • the rate at which the curve increases or decreases.
  • Whe does the curve increase in one case and decrease in another?

Normal Time:

• The time required for a “qualified” and “trained” worker/user to complete a task to “given standards” using a “standard method” under “given” conditions.
• Should include all or most -- not 50%

%Performance = Normal time/Average observed time * 100%

• 100% performance = normal time
• Normal time = Average observed time 𝗑 %Performance / 100%
• How to you determine the performance if you don't know the normal time and visa versa?
  • Educated guess, e.g.,
    • Football refereee calling pass interference
    • Diving judge
    • Gymnastics judge
  • Can be contentious
  • Generalize from benchmarks
    • Dealing 52 cards "neatly" into the corners of a 12x12" (30x30cm square) in 30s
    • Walking at 3 mph (4.4 fps or 1.34 mps) on a clear flat surface with good traction
  • Normal walking pace studies

  Table : Comfortable adult (20—79 years) walking speeds (average ± standard deviation, 5th %tile)-- What is normal?

  Age	Males	Females
  20-30	1.39±0.15, 1.14	1.41±0.18, 1.11
  30-40	1.45±0.09, 1.30	1.42±0.13, 1.21
  40-50	1.46±0.16, 1.12	1.39±0.16, 1.13
  50-60	1.39±0.23, 1.01	1.40±0.15, 1.15
  60-70	1.35±0.20, 1.02	1.30±0.21, 0.95
  70-80	1.33±0.20, 1.00	1.27±0.21, 0.92

• 230 healthy volunteers. Gait timed over a 7.6 m expanse of floor. (1 m/s = 3.281 ft/s)
• Bohannon, Richard W. Comfortable and maximum walking speed of adults aged 20—79 years: reference values and determinants. Age and Aging, 26.1 (1997): 15-19.

Standard Method:

A designaged sequence of steps for determine the normal time to complete a job/task to specified standards.

Normal Conditions:

The conditions that were observed and considered in the development of the normal time

Examples

Example 1: What would be the preformance of someone dealing a deck of cards as described above

• in 25s instead of 30s? Performance = 30s/25sx100% = 120%
• in 40s instead of 30s? Performance = 30s/40sx100% = 75%

Example 2: What would be the preformance of someone walking as described above

• at 2mph instead of 3mph? Performance = 2mph/3mphsx100% = 66%
• at 4mph instead of 3mph? Performance = 4mph/3mphsx100% = 133%

Example 3: What would be the normal time for dealing cards as described above if the observed time is 35 sec and the performance rating is 90%?

• Normal Time = 35s x 90%/100% = 31.5s

Example 4: What would be the normal time for someone who walks 50m in 37.3 s; because of snow and ice the worker is given a performance rating of 120%? What is a normal pace for these condtions/

• Normal Time = 37.3s x 120%/100% = 44.8s
• Normal pace for these conditions: 1.34 m/s/120%*100% = 1.2m/s

Example 5: A letter carrier requires 1min to walk to a house, but waits an average of minute for someone to come to the door and sign for the deliveries. What would be the normal time for this job if the worker is given a performance rating of 125%?

• Normal Time = 1.0min x 120%/100% + 1min = 2.2min (The rating applies only to the activity under the worker's control)
• Normal pace for these conditions: 1.34 m/s/120%*100% = 1.2m/s

What is the effect of setting up a serial production line based on average time to complete the job

• It is important all workers be able to complete the assigned work.
  • Work allocation and "line balancing"
  • Line speed

Allowances:

• adjustments for factors not directly considered in normal time
• Process: adjustments for abnormal events or conditions, eg., machine jams, unscheduled maintenance, material variations, etc.
• Personal: adjustments related to personal protective equipment, fatigue, extreme heat, cold, etc.
• Can be expresses in minutes or seconds per work cycle, for a given amount of work time or per work period.
• Can be expressed as % of work time (normal time) or % of total time (standard time)

Standard time:

• Normal time adjusted for additional process or personal factors
• Calculated (must be consistent with how allowance was defined)
• % of Normal Time (Work Time):
  • ST= NT + Allowance (minutes/second)
  • ST = NT(1+Allowance/100%)
• % of Standard Time (Total Time = Work Time + Allowance Time):
  • ST = NT / (1-Allowance/100%)

Document job/task & worker/user information that affects work performance

Time study documentation form

1. Job/task objectves & performance standards
2. Materials (hardwar or software): things that inform or become part of the product or a byproduct
3. Tools/equipment: things that are used to directly or indirectly to transform the raw materials into a final product
4. Workspace: spatial relationship between the worker and the worker Reach analysis app
5. Environment (physical and social)
6. Worker/user factors (qualified, trained, special needs?)
7. Work method (steps)
   1. Task 1
      1. Step 1.1
      2. Step 1.2
      3. Step 1.3
      4. Etc.
   2. Task 2
      1. Step 2.1
      2. Step 2.2
      3. Step 2.3
      4. Etc.
   3. Etc.
8. Define time study elements. Steps should:
   • Map into methods description
   • Share common purpose/goal
   • Follow a logical sequence
   • Be long enough to be measurable
   • Have conspicuous start/end points
9. Examples
   • Get case of product from pallet and place on cart; move cart to next pallet
   • Walk from house to house to deliver mail; deliver metters
   • Respond to text message with yes/no answer
   • Replace empty stock container with filled container
   • Find and get part
   • Prepare arm for vaccination, administer vaccination, apply adhesive bandage.
   • Don facemask

Time study logistics

• Supervisor permission
• Worker selection -- “qualified” & “trained” worker
• Verify normal conditions, equipment, materials, process
• Work permission
• Schedule observations

Prepare data collection from (add elements)

Time study data collection form

1. Record event times as observed (or from video)
   1. Clock time
   2. Element (lab) time
   3. Flag abnormal work elements
2. Record observed times for each time study element (as they are observed)
3. Elemental times
4. Performance rating
   • For each recorded time
   • For each element
   • For overall job
   • Record basis for rating (be prepared to defend it)
   • Bench Marks
     • Walking 3 mph clear unobstructed path
     • Dealing 52 cards into corners of 12”x12” (0.30mx0.30m) square in 30s
5. Record any differences from documented job documentation that may have affected your observations
6. Review data and flag all abnormal data
7. Copy all normal times to their respective columns in data collection form

Mail delivery

1. Documentation

Completion Standard: Put correct mail in each mail box along given route Materials: letters, magazines and packages < 5Kg Equipment: Mail truck Mail bag with shoulder strap <10Kg Workspace Mailstops 100 to 500 feet apparent Side walks Hills and Steps

Environment Outside in Michigan seasonal weather extremes (heat, rain, cold, snow, ice) Animals & insects Slip, trip & fall hazards, traffic hazards Interactions with supervisors, co-workers, customers, family, friends Time study elements: Walk to house Deliver -- Put “correct” mail in mailbox Get signatures as needed

2. Collect and process time study data

Record observed times; use Smart Phone, Stop Watch, or Time Study Web App Identify abnormal elements Rate performance Copy normal time elements to respective columns Calculate Average Elemental Time Apply Performance Rating Determine allowance Determine standard time

3. Time study Data & Results

n	ti	Δti	Element	Walk Δt1i	Deliver Δt2i	Comment
1	0.44	0.44	walk	0.44
2	0.55	0.11	deliver		0.11
3	0.98	0.43	walk	0.43
4	1.09	0.11	deliver		0.11
5	1.48	0.39	walk	0.39
6	1.6	0.12	deliver		0.12
7	2.14	0.54	walk	0.54
8	2.89	0.75	deliver		--	damaged mailbox
9	3.27	0.38	walk	0.38
10	3.36	0.09	deliver		0.09
11	3.73	0.37	walk	0.37
12	3.83	0.1	deliver		0.1
13	4.32	0.49	walk	0.49
14	4.41	0.09	deliver		0.09
15	4.69	0.28	walk	0.38
16	4.78	0.09	deliver		0.09
17	5.2	0.42	walk	0.42
18	5.32	0.12	deliver		0.12
19	5.71	0.39	walk	0.39
20	5.82	0.11	deliver		0.11
21	6.20	0.38	walk	0.38
22	6.32	0.12	deliver		0.12
23	7.02	0.7	walk	0.47
24	7.12	0.1	deliver		0.1
25	7.82	0.7	walk	0.43
26	7.92	0.1	deliver		0.1
27	13.65	5.73	walk	--		aggressive dog
28	13.76	0.11	deliver		0.11
29	14.11	0.35	walk	0.35
30	14.2	0.09	deliver		0.09
31	14.88	0.68	walk	0.68
32	14.97	0.09	deliver		0.09
33	15.36	0.39	walk	0.42
34	15.46	0.1	deliver		0.1
35	15.9	0.44	walk	0.44
36	16	0.1	deliver		0.1
37	16.49	0.49	walk	0.49
38	16.59	0.1	deliver		0.1
39	17.06	0.47	walk	0.47
40	17.16	0.1	deliver		0.1
41	17.59	0.43	walk	0.43
42	17.68	0.09	deliver		0.09
43	18.13	0.45	walk	0.45
44	21.06	2.93	deliver		--	stopped for signature
45	21.48	0.42	walk	0.42
46	21.57	0.09	deliver		0.09
47	21.92	0.35	walk	0.35
48	22.03	0.11	deliver		0.11
49	22.41	0.38	walk	0.38
50	22.53	0.12	deliver		0.12
51	23.04	0.51	walk	0.51
52	23.15	0.11	deliver		0.11
53	23.67	0.52	walk	0.52
54	23.78	0.11	deliver		0.11
55	24.04	0.26	walk	0.46
56	24.56	0.42	walk	0.42
57	24.66	0.1	deliver		0.1

Statistic	Walk Δt1i	Deliver Δt2i	Total
Min	0.35	0.09
Max	0.68	0.12
Median	0.43	0.1
Average	0.44	0.1
Std Dev	0.07	0.01
CV1(Std Dev/Avgx100%)	16%	10%
95%tile	0.53	0.12
Performance Rating2	110%	100%
Normal Tme3	0.48	0.1
Allowance (20cm of snow)	20%	0%
Standard Time (per element)4	0.58	0.1
Standard Time (per delivery)5			0.69

1(Std Dev/Avgx100%) 2based on bench marks, e.g., 3mph normal pace, and experience 3NT=Avg Observed Time x R/100% 420% of work or normal time. Total or ST = NTx(1+Allowance/100%) 5STtot=ST1+ST2