Fact vs. Assumption
Separate verified site measurements from unconfirmed assumptions to prevent costly decision errors.
About Fact vs. Assumption
Every construction field decision rests on a foundation of facts and assumptions. Facts are verified measurements, documented drawing references, and confirmed site conditions. Assumptions are unverified beliefs about what exists, what a drawing means, or how a trade will respond. When assumptions are treated as facts, decisions propagate errors downstream—often surfacing as rework, change orders, or disputes weeks later. This document provides a structured framework for labeling each piece of information as either a verified fact or an explicit assumption before it enters the decision pipeline.
The process is simple but rigorous: for every data point used in a field decision, the team must state the source and verification status. A measurement taken with a laser distance meter and cross-referenced against drawing A-101 revision 3 is a fact. A belief that the electrician will reroute conduit without a change order is an assumption. By making this distinction visible to all stakeholders, teams can prioritize which assumptions need formal verification through RFIs, submittals, or trade coordination meetings before proceeding.
Core Purpose & Scope
- To classify every input into a field decision as either a verified fact or an explicit assumption.
- To flag assumptions that require formal verification through RFIs, submittals, or trade coordination.
- To prevent unverified assumptions from being treated as facts in downstream decisions and change orders.
Critical Field Review Questions
Before treating any piece of information as a fact, the field team must answer these questions:
1. What is the source of this information?
For every data point, identify whether it came from a physical measurement, a contract document, a submittal, a verbal communication, or an inference. Only physical measurements and documented drawings qualify as facts. Everything else must be labeled as an assumption until formally verified.
2. Has this been cross-referenced against the latest revision?
A drawing dimension is only a fact if it was checked against the most recent issued-for-construction revision. Submittal approvals and architect's supplemental instructions can change dimensions after the original contract documents are issued. Always note the revision date and sheet number you verified against.
3. What happens if this assumption is wrong?
For each assumption, estimate the cost and schedule impact if it turns out to be incorrect. Assumptions with high impact must be escalated for formal verification before the decision proceeds. Low-impact assumptions can be noted and monitored, but should never silently become facts in downstream documentation.
Step-by-Step Implementation Guide
Follow these steps to separate facts from assumptions before making any field decision:
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List All Information Inputs:
Write down every piece of information that will inform the decision—measurements, drawing references, verbal instructions, trade feedback, and personal observations. Don't filter at this stage; capture everything that is being relied upon.
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Label Each Input as Fact or Assumption:
For each item, assign a label: FACT (verified by physical measurement or latest revision drawing) or ASSUMPTION (unverified, inferred, or verbally communicated). Record the source and verification method next to each fact, and the risk level next to each assumption.
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Escalate High-Risk Assumptions:
Identify assumptions that, if wrong, would cause rework, schedule delay, or cost overruns. Convert these into formal RFIs or trade coordination requests before proceeding. Low-risk assumptions can be documented and monitored, but must not be presented as facts in any downstream communication.
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