The data on productivity of resources is used in Estimation, Planning, & later in Controlling the Project Plan. Our estimates on cost and duration will go haywire if we do not have correct data on productivity. Even in day-to-day monitoring of works, the construction team must have the productivity data, else they would not be able to control and forecast the progress of works & their requirements for resources.
Just ask yourself, your peers, subordinates, contractors or even your managers about it; take one activity for example and ask the Labour or Equipment productivity for the same. Most likely you would be surprised as the data would have a large variation, sometimes to the tune of -500 to +500%. There are chances that some of them would not even know about the existence of such a term and their answer would be pure guess work.
If the awareness about resource productivity is that level, the knowledge about factors affecting the productivity, is far from the arena. Isn’t it the reason that we don’t even dream about improving the productivity of resources?
As explained in my earlier blog, the productivity data available in its present form is incorrect, erroneous, & padded up. Gross mis-representation of data, erratic changes in observations and the basis of the productivity calculations itself is wrong across a large number of organizations.
As an example, the activity of ‘Formwork for Slab & Beam’ includes the following:
- Survey Level / Grid markings
- Shifting Staging/Scaffolding Material (within 20/30m limit or previous pour by the side)
- Erection of Staging/Scaffolding
- Cleaning, Repairing/Closing holes etc. & Application of Shutter Release Compound
- Shifting Shuttering Materials (within 20/30m limit or previous pour by the side)
- Installation of Beam Bottoms, Beam Sides and Slab Bottom
- Alignment, Levelling and Final Firm Fixing of Shutters
- Installation of Starters & Keys etc. for Vertical Elements above
- Fixing Beam/Slab Stoppers at Construction Joint
- Installation of shutters for Pockets/Openings
- Offering Inspection of Formwork to allow pouring
- Taking care of formwork while pouring (aligning, if required & then removing keys at CJ) etc.
To get correct productivity for this activity the workers deployed for each of these items should be recorded, the quantity of the formwork to be calculated and then productivity to be arrived at.
If few items are ignored while recording workers deployed, the productivity figure would be deceptively high and thus the cost and time estimate would be low; causing the activity to go Over-Budget (Monitory Losses) and Over-Time (delayed) while executing.
To get correct data on productivity, an experienced professional need to guide the team in populating the list of all the activities and most importantly the items of works included or considered as part of the activity. To get representative data on productivity, large number of observations and documentation is needed for each of the activities. In fact, the observations must be collected from several projects during their entire life-cycle & then averaged out. Keep checking for standard deviation; which should be within limits, say 20%.
Apart from these also observe the following factors (there are several more factors, but these are the most important ones) which affect the productivity & and document the same for each of the observations (for all activities/ in various projects):
- Degree of Mechanization
- Skill & Experience level of workers
- Location, Type & Size of Project
- Level of Congestion in works
- Atmospheric Conditions (Temperature/Humidity/Rain)
Since these observations about the factor would be very subjective, experienced professional is needed to guide the team observing and recoding this particular data. Normally these are recorded as based on Severity Levels of these factors ranging from Excellent to Very Poor i.e. the productivity would be high or low based on factors. e.g. High Degree of Mechanization would result in better productivity thus it can be recorded as ‘Excellent’ or ‘Very Good’; whereas High Level of Congestion would result in lower productivity, hence it has to be recorded as ‘Very Poor’ or ‘Fair’
Since the conditions are existing while recording productivity data the whole exercise will give ‘Average Factored Productivity’ along with severity of factors. Again, an expert advice would be required to eliminate the impact of factor and then we get ‘Standard Productivity’ for an activity. You would notice that the figure of ‘Standard Productivity’ would then have a standard deviation of only 3-4 %.
Once you get Standard Productivity, you can use it in any future project. You just have to tailor it based on the severity level of the above listed factors in that project.
Although it a very detailed & time-consuming exercise but is vital for any organization as their entire business depends on the Estimation of Time and Cost.
ADGP www.decodingcm.com/pm-blogs https://decodingcm.blogspot.com