From pipe to payroll: a five-resource chain

A worked example of the loaded labour rate build-up within the Global Variables methodology. One supply-and-install pipe rate, built entirely from linked resources, cascading down through a drainage crew, an excavator, its operator, and the labour living-out allowance that operator can draw on.

The main paper describes Global Variables as a dependency graph rather than a static spreadsheet: change one input and every calculation referencing it recomputes in place. What that graph looks like across several linked resources is harder to show in the abstract, so this worked example of the loaded labour rate build-up follows one real chain end to end. A supply-and-install rate for 450mm RCRRJ pipe does not price its own labour and plant, it calls a drainage crew resource. That crew does not price its own excavator, it calls an excavator resource. The excavator does not price its own operator, it calls an operator resource. And the operator’s loaded rate carries a line for a labour living-out allowance, priced as its own resource and switched on or off per crew. Five spreadsheets, one live chain, and every figure below is the model as it runs.

The chain, pipe to payroll

Reading top to bottom: each card is a full Global Variables resource in its own right, and the line joining it to the card below is not a copied number, it is a resource reference. Change the operator’s base wage and the excavator rate, the crew rate, and the installed pipe rate all recalculate without anyone touching four other spreadsheets. Click any card to jump straight to its full build-up.

Zooming into one link: loaded labour rate build-up

The operator resource is one card in the chain above, but it is itself a small graph. A single base wage feeds overtime brackets, four statutory percentages uplift the combined payroll figure, and annual allowances are converted to an hourly equivalent and added last.

The full build-up, resource by resource

Each tab below is one exported Global Variables resource, the same five spreadsheets shown in the chain above, in the same order, with every group and line item intact. Equations reference variables in brackets; a variable defined in one row is available to any equation elsewhere in that resource, and a resource line highlighted in blue is itself a pointer to an entire second sheet rather than a hardcoded price.

Reading the variable codes

Each bracketed code is a live pointer into its own resource, not a copied figure. The glossary below covers the codes used within the operator resource; the pipe, crew and excavator resources each carry their own local set following the same pattern, for example LOC and PD in the pipe resource, or WACC and KW in the excavator resource.

Why this matters beyond one rate

The same four percentage variables, PL_GV, CA_GV, RC_GV and AC_GV, appear twice in the operator sheet: once combined into the total uplift multiplier near the top, and again individually further down where each is actually defined. In a spreadsheet, that means two places to update and two chances for them to drift apart. In the Global Variables model, both references point at the same underlying value, so a change to a statutory rate is entered once and is correct everywhere it is used, including in every other estimate, resource, and cost plan built on the same variable.

Scale that principle from one loaded labour rate to a project with thousands of resources, and the value of the dependency graph compounds: a single wage negotiation, insurance renewal, or allowance change is entered once and recalculates every affected line automatically, with a full audit trail back to the source variable.

This worked example shows the same principle stretched across five resources instead of one sheet. Raise the operator’s base wage by a dollar and the excavator’s wet rate moves, the drainage crew’s day rate moves, and the installed rate for 450mm RCRRJ pipe moves with it, all without a single manual re-key. Switch the labour living-out allowance on for a remote job and the same ripple runs the other way: one toggle, and the crew day rate, the pipe rate, and every estimate built on this crew update together.