In analyzing productivity it is sometimes better to look at the number in its inverse value. Don’t know what the Inverse is? Pretty simple and important math function to know. So let us say you have a number like 1000. What is its inverse?

1/1000 = 0.001 So the inverse is just the number divided into 1.

So what is the application in HeavyBid? The short answer is the productivity factors that drive the crew hour calculations. Below is a list of these factors.

HeavyBid Productivity Values

So the factors that have inverses are UH/HU, MU, UM and US/SU. The estimator selects the factor that makes the value itself understandable. For example lets say it takes 12 hours to install a storm structure. If the estimator uses UH or Units per Hour then the rate would be 1/12 or 0.0833 structures per hour. To an estimator this usually is not a value that we have stored in our memory to check against. But we take the inverse of it and use HU then we have 12 hours/each which makes sense. So both values, 0.0833 and 12 will yield the same crew hours if the correct productivity value is applied and one is the inverse of the other.

Another example. From accounting productivity reports for 24″ RCP storm pipe the average production for the project is 0.0333 MH/LF. Accounting programs can only produce productivity values of MU or UM (unlike HeavyJob which can give you values for Units per Shift). So here is how I would make this value makes sense to me.

1/0.333 MH/LF = 3 LF/MH or 1 man can lay 3 feet in an hour. Now consider the crew size of 5 people.

3 LF/MH x 5 MH/HR = 15 LF/Hour or for a 10 hour day this would be 15 x 10 = 150 LF/Shift.

This is basically 5th grade math and any estimator worth his or her salt can make these calculations. In the HeavyBid Cost Report you can see the inverse values of some of the productivities calculated. Also in Queries you can customize a Query for inverse productivity values.

In conclusion start using inverse values where it makes sense and know show to use an inverse calculation to produce a value that makes logical sense to you as an estimator.