Editorial policy

Where the numbers come from, and who is accountable for them

This site publishes figures that people use to size conductors, price jobs and decide how to spend several thousand dollars. This document states the sourcing standards those figures must meet, how they are dated and reviewed, how production is controlled, and how errors are corrected.

Last updated: September 2026
Correction acknowledgement: 3 business days
Affiliate relationships: None

Scope and standard

This policy applies to everything published on truetradepath.com: calculators, cost guides, trade and career pages, licensing summaries, diagnostic guides and directory listings.

The standard is simple to state and expensive to keep. Every quantitative claim must be traceable to a named source or to our own deterministic calculation from a named source, must carry the date or period it refers to, and must be accompanied by the assumptions that make it meaningful. A figure that cannot meet that standard is not published, even where a plausible number could be assembled from context.

Where sources conflict, we publish the range and name the disagreement rather than picking the midpoint and presenting it as consensus. Where a question has no reliable answer, we say the answer is not reliably known.

Sourcing standards

Sources are used in a fixed order of preference: primary government data, then the published codes and standards themselves, then manufacturer documentation, then peer reviewed or association research, then trade press. We do not cite another aggregator’s summary of a figure when the underlying dataset is available.

Wages and employment

Sources used: U.S. Bureau of Labor Statistics — Occupational Employment and Wage Statistics for wage levels and percentiles, Employment Projections for growth and annual openings, and Current Population Survey data where occupational detail requires it.
How we publish it: We publish the median together with the 10th and 90th percentiles, because a median alone conceals the spread that actually determines what a given job pays. Every wage figure carries its survey period. We do not average across survey vintages or blend BLS figures with self-reported salary data.
Review cadence: Reviewed on each BLS release, at least annually.

Electrical calculations

Sources used: The National Electrical Code (NFPA 70) — ampacity and conductor tables, conduit fill and raceway dimensions, box fill volumes, dwelling-unit load calculation methods, and voltage-drop guidance.
How we publish it: The code edition used by a tool is stated in the tool. Where a jurisdiction has adopted an older edition, or has amended the adopted edition, the local requirement governs and our output does not. We reproduce no code text beyond what fair use permits; the code itself must be consulted for authoritative language.
Review cadence: Reviewed against each code cycle and on publication of a new edition.

Plumbing and mechanical calculations

Sources used: The International Residential Code and International Plumbing Code for fixture units, water and drainage pipe sizing, venting and combustion air; ACCA Manual J, S and D methodology for load and duct sizing.
How we publish it: Sizing outputs are stated as the size the method produces under the assumptions shown, not as the size your jurisdiction will approve. Fixture-unit and load methods vary between adopted codes, and some jurisdictions use the Uniform Plumbing Code instead; the tool states which method it applied.
Review cadence: Reviewed against each code cycle and on publication of a new edition.

Equipment service lives and performance

Sources used: Manufacturer installation and specification documentation, ASHRAE and ACCA research, and published studies from industry associations such as NAHB, InterNACHI and trade-specific bodies.
How we publish it: Service life is published as a range with the conditions that move it — water chemistry, maintenance history, run hours, climate. A single-number life expectancy is not a defensible figure and we do not print one.
Review cadence: Reviewed annually.

Costs and pricing

Sources used: Published contractor pricing, regional construction cost indices, material pricing from distributor catalogues, and Producer Price Index series for material escalation.
How we publish it: Costs are published as ranges for a described scope, with the collection period and the region basis stated. Regional adjustment is applied by index, not by guess. We do not publish a national average as though it were a quotable price.
Review cadence: Reviewed at least twice a year, and sooner when material pricing moves sharply.

Licensing and apprenticeships

Sources used: State licensing boards and contractor registration agencies, the U.S. Department of Labor and state apprenticeship agencies for registered programs, and recognised accreditors for training providers.
How we publish it: Requirements are attributed to the issuing authority and dated. Where a state's published guidance is ambiguous we say it is ambiguous rather than resolving it ourselves, and we point to the authority that can answer it.
Review cadence: Reviewed annually and on notification of a rule change.

How figures are dated and reviewed

A number without a date cannot be evaluated, and a number that was right three years ago is often worse than no number at all. Four rules govern dating on this site.

Every dataset carries a vintage. Wage figures state the survey period. Projections state the projection decade. Cost ranges state the collection period. Code-derived tools state the code edition.
Every page carries a last-reviewed date. The date means a person checked the figures against their sources on that day. It does not mean the page was edited, and we do not refresh it to make a page look current.
Stale figures lose their claim. Where a source has released newer data that we have not yet incorporated, the page says so. Where a figure has passed its review window without being re-checked, it is flagged as under review rather than presented as current.
Code editions are never implied. Because jurisdictions adopt different editions on different schedules, a calculation is always labelled with the edition it implements, and the page states that the locally adopted edition governs.

The use of AI in production

We use AI tools in building this site, and we would rather tell you exactly how than let you assume either extreme. They are used for drafting prose, structuring data files, writing and reviewing code, and generating test cases. They are not used to produce facts, and they are not a substitute for review.

A language model is a fluent generator of plausible figures and plausible citations, which makes it actively dangerous in a subject where a wrong number becomes a conductor that overheats or a quote accepted at twice its fair price. The following rules are therefore absolute.

No page is published from model output alone. A person reviews every page before it goes live and is accountable for what it says.
Numbers are never generated by a language model. Every figure is taken from a named source or computed by our own deterministic code from a named source. A model may help structure a data file; it does not supply the values in it.
Calculator logic is written and reviewed as code against the published method or code section it implements, and is checked against worked examples. No tool computes its answer by asking a model.
Code references, licensing requirements and safety-relevant statements are checked against the primary source by a person. A plausible-sounding citation is treated as no citation.
Where a model has been used for drafting, editing or summarising, the human reviewer verifies every factual claim and every citation in the draft. Claims that cannot be traced to a source are removed rather than softened.
We do not publish model-generated text as a quotation, an expert opinion or a first-hand account of work performed.

The human review requirement

No page reaches publication without a named person having reviewed it and confirmed that every figure traces to its source, every code reference matches the cited section, every assumption is stated, and every limit is disclosed. Accountability for published content rests with that person and with True Trade Path. It is never delegated to a tool.

Corrections

We will make errors. The measure of an editorial operation is not whether it makes them but what happens next.

Report an error to corrections@truetradepath.com, with the page address, the specific statement or figure at issue, what you believe is correct, and a source we can check. For a calculator, include the exact inputs you used so we can reproduce the output.

What we commit to

Acknowledgement of every correction request within three business days.
Resolution of substantiated corrections within ten business days of acknowledgement, or an explanation of why it will take longer.
Immediate correction of any error that materially changes a calculated result, a published range or a safety-relevant statement, without waiting for the next review cycle.
A dated correction note on the page itself for substantive changes, describing what was wrong and what it now says. We do not silently overwrite a figure.
Where an error affected a tool’s output, a statement of the period during which the output was wrong, so anyone who relied on it can recheck their work.

What is not a correction

A disagreement with a range is not an error in it. Where a contractor believes our published costs are too low, or a homeowner believes they are too high, we will re-examine the underlying data and publish a revision if the data supports one. We will not adjust a range because a party prefers a different number, and we do not remove accurate figures on request.

Conflicts of interest

The site is funded by display advertising. That is the only commercial relationship permitted to touch it, and these rules keep it at a distance.

No individual involved in producing this site accepts payment, equipment, discounted services, travel or gifts from an organization that appears in our listings, from a manufacturer whose products we reference, or from an advertiser.
Advertising is sold as display inventory only. Advertisers receive no advance notice of what we publish, no review of copy, and no ability to request changes to editorial content, tool logic or verification outcomes.
We operate no affiliate program and hold no commission arrangement with any retailer, manufacturer or contractor. No recommendation on this site earns us a commission.
Where a person contributing to a page holds a material interest in the subject — ownership of a business in the trade covered, a paid role with a manufacturer or association named on the page — the interest is disclosed on the page or the person does not work on it.
We do not accept paid links, sponsored posts, guest contributions or paid mentions in any form.

The placement constraints that apply to advertising are set out in the advertising disclosure. The commitments covering listings, ranking and reviews are on the trust and methodology page.

Standing disclaimer

Nothing on this site substitutes for a licensed professional or an adopted local code

The tools, guides, cost ranges and calculations published by True Trade Path are planning aids. They are not professional, engineering, legal, tax or insurance advice, and they are not a determination of what any jurisdiction will permit or approve. Code requirements are established by the edition of the code your jurisdiction has adopted together with local amendments, and are interpreted and enforced by the authority having jurisdiction. Where work is subject to permit or inspection, where gas, electrical, structural or life-safety systems are involved, or where an error carries risk of injury or property damage, the work must be designed, performed or reviewed by an appropriately licensed professional. Confirm every figure that matters against the adopted code and a professional who has seen the site.

This disclaimer is not a formality attached to the end of a policy. It is the condition on which the rest of the site is offered, and it is repeated on the pages where it applies most directly. The full terms governing use of the site are in the terms of use.