Step 4 - Use Primary Production as a Local Variable

Most pricing sheets will typically contain a labor or equipment component that has a time-related unit of measure, per day/per hour, which means that in order to transform that time-related unit of measure to a physical unit of measure like yd2 we need to apply a production rate, i.e., how many square yards can be produced per day?

We always divide by the production rate, as we need to determine what is our per yd2 cost, so if you think back to our Plastering example, if a general construction worker is paid $20 per hour of labor, work for an 8-hour shift and can plaster 30 yd2 per shift, then it costs us $5.33 (160/30) per laborer per yd2 of plaster.

This is why the transform calculations in the Plaster pricing sheet looked like this:

However, imagine that the general laborers are only mixing mortar and making sure the plasterer has it to hand. And they could actually mix enough mortar for 60 yd2 per day. Would it make sense to use a production rate of 50 for the general laborers?

No, because the plasterer can only plaster at a rate of 30 yd2 per day, so he is the constraining resource that ultimately determines the output and speed at which the item can be completed.

Thus, we can use the production rate of our plasterer to define our primary production rate @p as 30 and a better way to model our pricing sheet is then as follows:

It is a good habit to always define @p for each pricing sheet and to use it in all transform calculations requiring a production rate on the worksheet.

Firstly, it will make life easier for you in being able to easily update any worksheet should the production rate for a line item on a specific project increase or decrease due to various project-specific factors.

Secondly, the @p production factor is very important for the planning, scheduling, and forecasting section of Trimble Quest, as it will be used to calculate activity durations, so it is very useful to have it built in from the start as you are creating your library.