Methods of measurement: define and check the basis of each BOQ item
Methods of measurement define what a quantity in a BOQ item represents: its unit, measurement boundary, deductions and separately described components. Different results from the same drawing do not necessarily indicate an arithmetic error; they may follow different rules. Before changing a figure or using it for pricing, identify the source and instruction behind each calculation.
Which methods of measurement apply to the project?
Start by collecting the available project documents: the bill of quantities, specifications, drawings, clarifications and instructions provided for measurement. Identify the relevant revisions and what the project documents say about their applicability and order of precedence. A specification name or chapter number alone does not explain how a particular item should be calculated. If an instruction is missing, raise the question and identify any proposed assumption rather than treating it as already agreed.
In a BOQ using a familiar Israeli chapter structure, chapter numbering helps organise the work. It does not establish that a particular document's measurement rules have been applied to every item. State the adopted measurement basis and any project-specific exceptions. It is also useful to distinguish a document describing work scope from a source of prices; the guide to specifications and price lists discusses that distinction. A price from a database does not replace checking the item description and the extent of the work.
Record enough information to review each item
A useful explanation begins with the unit and measurement boundary, then identifies the source and the rules that affected the calculation. For a finishing area, for example, establish which surface is measured, how openings were treated and whether associated components are in the same item. Do not apply one deduction threshold to every material or project. Even when a value comes from a model, check that the selected parameter represents the quantity the BOQ item requires.
| Check | Record |
|---|---|
| Unit and boundary | Area, volume, length or item count; the building, floor and zone included |
| Source | Drawing and revision, table or model export, with a reference that can be followed |
| Measurement instruction | The relevant document and clause, including any project-specific instruction or clarification |
| Adjustments | Deductions, additions and component splits, with a reason for changes to the source value |
| Review status | Agreed instruction, unresolved working assumption or information still missing |
Keep the original value separate from adjustments. This makes it possible to investigate whether a discrepancy arose in reading the drawing, applying the rule or summing the results. A quantity calculation file connects the BOQ item, formula and source so that the change can still be traced when a new revision arrives.
Measurement, classification and estimating serve different purposes
When a project includes documents from another country, check what each document is intended to do. The British NRM suite, for example, separates cost estimating and cost planning, detailed measurement for building works, and cost planning for maintenance. Naming the suite is insufficient: identify the relevant document, edition and requirements adopted for the project. Do not assume that a particular item's rules are identical across those documents.
CSI classification systems organise information and work descriptions. Placing an item in the appropriate category helps readers find it, but does not by itself explain how your project's quantity was measured. Likewise, an estimate based on a building's floor area is not a substitute for detailed measurement of every item. The practical distinction is between organising information, calculating quantities and assessing costs. Each requires an explicit basis.
When translating a BOQ into English, preserve the unit, scope and calculation basis. Translating an item heading word for word is insufficient if the reader understands it to cover different work. If adapting to another method is required, document the changes and the review performed. Changing only the method's name at the top of an otherwise unchanged workbook does not establish that the items follow it.
Investigate a discrepancy before removing or adding work
Suppose one item describes work that includes an associated component, while that component also appears separately elsewhere. This illustrative case calls for a scope check; it does not automatically prove double counting. The second item may concern a different area or a special requirement. Identify both items, attach their sources and clarify their boundaries before deleting a quantity or adding a cost.
A quantity difference needs a traceable explanation. Record the items, units, sources, differing instructions and unresolved question. An agreed change carries a date and a reference to the clarification. An assumption awaiting agreement remains labelled as an assumption.
After clarification, update both the calculation and the item description, and check that the change reaches the totals. Keep the previous version for comparison. If the quantity will be used for procurement, separately examine adjustments such as packaging or waste allowances: these do not automatically follow from a pricing quantity. See the guide to physical, BOQ and order quantities.
A quantity surveyor may be an engineer or a registered building technician, like Yaakov Avital. The quantity surveyor reviews descriptions, units and sources alongside the calculations. Explicit methods of measurement help the client and the person pricing the work understand the basis submitted for review and which questions still require a professional response.
Frequently asked questions
Are methods of measurement the same for every BOQ?
Do not assume so. Check what the project documents adopt, which edition is used and what has been specified for special items. Rules from a previous project may help identify questions, but they do not establish which rules apply to the new project.
Is a model quantity already suitable for pricing?
Not necessarily. Identify what the parameter measures, its unit and what it includes, then compare it with the item's requirement. The value may be usable as it stands or may require a documented adjustment before inclusion in the BOQ.
What if a clear measurement instruction is missing?
Identify the gap to the relevant project professional and ask a focused question. If a working assumption is needed to proceed, state it and explain its effect on the quantity. Do not mark the item as resolved before the required clarification has been completed.
Have a project? Tell me briefly what the project is and what already exists. When the project is a good fit, I usually reply with focused questions and a written quote.
Contact me for a quote* Created with AI for marketing, for illustration only. Not reviewed by Yaakov Avital and not professional advice. Every project must be checked on its own by a professional quantity surveyor and an engineer.