Production rate, Efficiency, Effectiveness, Performance

Transcription

1 PRODUCTIVITY Agenda What is productivity? Production rate, Efficiency, Effectiveness, Performance or Production Factors Affecting Productivity General Productivity Model 09/11/2014 Emad Elbeltagi 2 1

2 Productivity Productivity is defined as: The proportion obtained by dividing output by one of the factors of production input. Or it the ratio of total output produced to the input of one element of production Total productivity is the ratio of total output produced to the total inputs used It is not necessary that the greater the production, the greater the productivity 09/11/2014 Emad Elbeltagi 3 Definitions Productionis concerned with the activity of production goods and services Production rate is the quantity of total production produced in unit of time (كفاءة) Efficiency in general describes the extent to which time or effort is well used for the intended task or purpose (فاعلیة) Effectiveness means the capability of producing 09/11/2014 Emad Elbeltagi 4 2

3 General Productivity M odel INPUT SYSTEM OUTPUT Capital Labor Material Equipment Energy Transformation Goods Services 09/11/2014 Emad Elbeltagi 5 Total and Partial Productivity Total productivity is the ratio of the total output produced to the total inputs used Total output Total Productivity = Total inputs Total output Total Productivity = (labor+ material+ equipment) inputs 09/11/2014 Emad Elbeltagi 6 3

4 Total and Partial Productivity Partial productivity is the ratio of the total output produced to the input of one element of production Total output Partial Productivity = Input of one production element Total output Labor Productivity = Labor input Material Productivity = Total output Material input 09/11/2014 Emad Elbeltagi 7 Construction Productivity Facts Best time for labor production is 10am 12pm Labor need 10-15% of work time as rest time In repetitive jobs. Labor productivity decrease after 60:70 min Labor productivity is min before lunch time and at the end of the day labor productivity is max when works 5 days a week, 8 hours a day Productivity of first shift is more than second shift Labor productivity affected by overtime for long time Accidents happen during unproductive time, productive time is safe Most injuries happen on Saturday and Thursday 09/11/2014 Emad Elbeltagi 8 4

5 W ork Time Components Actual Work Time Total Work Time Basic Work Time Unnecessary Work Time Inefficient Time (Poor Management) Time consumed in construction if design and specification are correct, equipments are efficient. Extra work due to design mistakes Extra work due to inefficient construction methods Lost time due to labor shortage Lost time due to exceptional conditions 09/11/2014 Emad Elbeltagi 9 Productivity M easure Productivity is not simply performanceand not the efficient use of resources, but a combination of both Its measurement is carried out by means of ratios: Output variables: units produced; products sold; tasks completed; or revenue obtained Input variables: the number of people employed; hours worked; capital used; material costs 09/11/2014 Emad Elbeltagi 10 5

6 Productivity M easure Average labor productivity Total output Labor Productivity = Labor input Total output = Man-hours of Labor input Marginal labor productivity: The impact on production when adding one more unit of labor while keeping other factor fixed Marginal Labor Productivity = Increase in output One unit of man-hour 09/11/2014 Emad Elbeltagi 11 Productivity M easure Example 1: A construction company produces 1,000 blocks by employing 40 workers at 7 hours/day for one month. Assume this month has a 25 working days. What are the production rate and productivity of labor? Production rate = 1,000 Blocks/month Labor productivity = 1,000 Blocks 40 workers x 25 days x 7 hrs/day Labor productivity = 1 Block/ 7 man-hours 09/11/2014 Emad Elbeltagi 12 6

7 Productivity M easure Example 2: Suppose this company increased its production to 1,500 Blocks by employing 30 additional workers at 7 hours/day for one month, this month has a 25 working days. What are the production rate and productivity of labor now? Production rate = 1,500 Blocks/month 1,500 Blocks Labor productivity = (40+30) workers x 25 days x 7 hrs/day Labor productivity = 1 Block/ 8.2 man-hours The production of blocks has gone up by 50% The labor productivity gone down by 17% Increased production does not mean increased productivity 09/11/2014 Emad Elbeltagi 13 Factors Affecting Productivity Industry related factors Government Research and development Weather Building code and specification 09/11/2014 Emad Elbeltagi 14 7

8 Factors Affecting Productivity Project related factors Project design Design changes Method of construction Type of contract Location Type of project Work type 09/11/2014 Emad Elbeltagi 15 Factors Affecting Productivity Labor related factors Supply and demand Unions rules Crew composition Crew size Skills Capabilities Motive 09/11/2014 Emad Elbeltagi 16 8

9 Factors Affecting Productivity Management related factors Planning and scheduling: Lack of project planning and scheduling is one of the important reasons of low construction productivity. Planning a project can reduce production costs by increasing productivity of craftsman and optimizing utilization of available resources. 09/11/2014 Emad Elbeltagi 17 Factors Affecting Productivity Management related factors Control: Problems arise every day that could not have been foreseen. Adverse weather, Material delivery delays, Labor disputes and Job accidents Can disrupt the original plans. Without time control, rescheduling could not accomplished and so productivity will suffer due to lack of coordination and communication and resource shortage. 09/11/2014 Emad Elbeltagi 18 9

10 Factors Affecting Productivity Management related factors Project organization: The main task of any organization is to plan, direct and control Poor organization results in poor productivity Defining individual positions of authority and responsibility will lead to an effective operating environment and good productivity. 09/11/2014 Emad Elbeltagi 19 Factors Affecting Productivity Management related factors Supervision: Although unnecessary supervision will increase the cost of work, insufficient supervision will result in confusion delays and decrease productivity. The labor productivity is increased by increasing the number of man hours per day that the field supervisor spent in contact with the crew. 09/11/2014 Emad Elbeltagi 20 10

11 Factors Affecting Productivity Management related factors Materials and tools availability: Unavailability of material and tools had a significant adverse impact on the productivity of labor. Material unavailability loss between 6.4 and 8.4 % of total time. When material management programs are applied in any project, a minimum 6% improvement in labor productivity achieved. 09/11/2014 Emad Elbeltagi 21 Factors Affecting Productivity Management related factors Rework and Delays: Re-work maintained a position as one of three worst problems leading to poor productivity. The amount of times spent on rework is between % of total time. Causes of rework are mainly due to engineering and management inefficiencies. Craftsmen spent an average of 14.3% of their time redoing work. 09/11/2014 Emad Elbeltagi 22 11

12 Factors Affecting Productivity Management related factors Lack of motivation of workers The greater the worker motivation, the greater labor expenditure of effort. Lack of material, frequent change orders, conflict of crews because of improper scheduling, lack of equipment, etc. frustrate the worker and produce low productivity. 09/11/2014 Emad Elbeltagi 23 Factors Affecting Productivity Management related factors Site layout Site layout is a very important organization task. The assigned location of different job components affects productivity, safety, workers satisfaction, and communication. Approximately, 7% of a day is nonproductive because of a non proper site layout. 09/11/2014 Emad Elbeltagi 24 12

13 Productivity V s. Quality Quality means; inspection, quality control, quality assurance, and total quality management Low quality of construction will cause re-work Re-work affects the production rate and decrease the output When output decreases, productivity decreases 09/11/2014 Emad Elbeltagi 25 Improving Productivity Generally: Replace labor with equipment and/or Replace old equipment with modern equipment To increase productivity Increase output and decrease input Increase output or decrease input High rate of output increase and low rate of input increase Low rate of output decrease and high rate of input decrease 09/11/2014 Emad Elbeltagi 26 13

14 Improving Productivity Inspire Your Workers Improve Communications Lay Out A Productive Jobsite Schedule Your Work Analyze Project Reports Manage Equipment Productively Improve Safety Pay Attention To Quality 09/11/2014 Emad Elbeltagi 27 Productivity M easure Example 3: The following data are given for a construction operation: Quantity of work = 4680 units; Number of laborer = 4 laborers Normal conditions: 42 hours/workweek 7 hours/day 6 days/week; Productivity = 3 units/man-hour; Labor cost = 3 L.E./hour/labor. Scheduled conditions: 60 hours/workweek 10 hours/day 6 days/week; Productivity = as shown in table; Labor cost = 3 L.E./hour/labor (for 7 hour/day) & 4.5 L.E./hour/labor (for hours over 7 hour/day). Calculate the duration and labor cost for this operation in the following cases: Normal conditions and Scheduled conditions? Compare between the results of both cases? Week number Av. Commutative% normal production rate /11/2014 Emad Elbeltagi 28 14

15 Productivity M easure Normal conditions: Duration = quantity / production rate Quantity = 4680 units Production rate = 3 units/man-hours x 7 hours/day x 6 days/week x 4 labors = 504 units/week Duration = 9.3 weeks Cost = 3 LE/man-hour x 7 hours x 6 days/week x 9.3 weeks x 4 labors = LE 09/11/2014 Emad Elbeltagi 29 Productivity M easure Scheduled overtime: For 9 weeks: Duration = quantity / production rate Quantity of Production = (3 units/man-hours x 0.66) x 4 labors x 10 hours/day x 6 days/week x 9 weeks = units For 10 weeks: Quantity of Production = (3 units/man-hours x 0.65) x 4 labors x 10 hours/day x 6 days/week x 10 weeks = 4680 units Using scheduled overtime will take 10 weeks Cost = (3 LE/man-hr x 4 labors x 7 hrs x 6 days/week x 10 weeks) + (4.5 LE/man-hr x 4 labors x 3 hrs x 6 days/wk x 10 weeks) = 8280 LE Overtime should not be implemented for long time Overtime may not save time or money Using overtime should be limited to follow up with late project schedule 09/11/2014 Emad Elbeltagi 30 15

16 Quiz A concrete mixer can produce 50 m3 of concrete by employing 5 workers for 8 hours/day. Daily rate of one worker is 50 L.E/day. This daily production can be increased to 100 m3/day by employing 3 more workers at the same rate. Calculate the labor productivity for both cases. Explain your answer Decide whether to employ the additional workers or not 09/11/2014 Emad Elbeltagi 31 THANK YOU 16